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el-retired/elc-combined.el
T
Will Anderson 5c05ce9b99 self-host the el compiler
Today's milestone: dist/platform/elc compiles itself byte-for-byte to
itself (stage1 == stage2 == stage3 verified). The compiler is now a
real binary in the world.

What landed
- Spec rewrite (language.md) to truth — every feature marked
  implemented / planned / not-in-this-language with no fiction.
- C runtime extension: 51 new builtins. JSON parser + accessors,
  time, UUID, env, in-process state K/V, float formatting + math,
  string ops (index_of, split, char_at, char_code, pad_left/right,
  format), list ops (push, push_front, join, range), bool_to_str.
  Runtime grew 631 → 1611 lines, header 171 → 247.
- Codegen fix: transform_implicit_return lifts a function's bare
  trailing expression into an explicit return. Without it, lex(),
  parse(), and every other implicit-return function returned 0/nil
  and the whole pipeline produced empty C output.
- Codegen fix: index expressions dispatch on AST kind. obj["literal"]
  → el_get_field (map), arr[i] → el_list_get (list). Same Index node
  in the parser, two different runtime calls.
- Codegen fix: skip emitting fn main() (collides with C main()) and
  honor parsed return-type annotations so Void functions don't get
  return-wrapped (return println(x) is a C type error).
- Parser: capture return-type identifier from -> Ret annotations.
- Lexer: + vessel keyword, + % operator, + \r escape.
- Runtime fix: el_list_append now allocates a fresh list rather than
  realloc'ing the input. Realloc moved blocks made caller pointers
  dangle, which was inserting garbage values into declared lists and
  causing strcmp segfaults. Persistent allocation eliminates the
  whole class of use-after-free at modest memory cost.

Bootstrap path
- One-shot Python helper translated elc-combined.el to C and
  produced stage1. Helper is disposable; not committed.
- stage1 compiles elc-combined.el → stage2.c which cc compiles to
  stage2; stage2 compiles elc-combined.el → stage3.c. stage2.c and
  stage3.c are byte-identical. Closure proven.
- New elc installed at dist/platform/elc; old broken binary
  preserved as dist/platform/elc.legacy.
- dist/platform/elc.c is the canonical generated source.
- elvm and the bytecode pipeline are no longer on the critical path.

Known gap
- The `+` operator's heuristic dispatch still picks string concat
  when both operands are Idents with no literal anchor. Self-hosting
  works because the compiler source is careful, but `fn add(a:Int,
  b:Int) { a + b }` will not do arithmetic until codegen reads the
  parsed type annotations to dispatch. Fix is wiring; not done here.

Tested
- tiny / lextest / whiletest / map+field / array build all run.
- cgi-studio (1037 lines real El) compiles to C cleanly. Link fails
  only because runtime is missing fs_list, json_encode, llm_*; those
  are scheduled batches.
- Three-stage closure (stage1 vs stage2 vs stage3) byte-identical.
2026-04-30 13:10:29 -05:00

2082 lines
78 KiB
EmacsLisp

// elc-combined.el El self-hosting compiler, single-file bootstrap edition
// Inlines lexer + parser + codegen CLI entry at end.
// lexer.el el self-hosting lexer
//
// Tokenises an el source string into a list of token maps.
// Each token is a Map<String, Any> with keys:
// "kind" -> String (e.g. "Int", "Ident", "Plus")
// "value" -> String (the raw text of the token)
//
// Entry point: fn lex(source: String) -> [Map<String, Any>]
//
// Uses native_string_chars to split the source into a chars list,
// then indexes it with native_list_get avoids O(N²) string cloning.
// Character helpers
fn is_digit(ch: String) -> Bool {
if ch == "0" { return true }
if ch == "1" { return true }
if ch == "2" { return true }
if ch == "3" { return true }
if ch == "4" { return true }
if ch == "5" { return true }
if ch == "6" { return true }
if ch == "7" { return true }
if ch == "8" { return true }
if ch == "9" { return true }
false
}
fn is_alpha(ch: String) -> Bool {
if ch == "a" { return true }
if ch == "b" { return true }
if ch == "c" { return true }
if ch == "d" { return true }
if ch == "e" { return true }
if ch == "f" { return true }
if ch == "g" { return true }
if ch == "h" { return true }
if ch == "i" { return true }
if ch == "j" { return true }
if ch == "k" { return true }
if ch == "l" { return true }
if ch == "m" { return true }
if ch == "n" { return true }
if ch == "o" { return true }
if ch == "p" { return true }
if ch == "q" { return true }
if ch == "r" { return true }
if ch == "s" { return true }
if ch == "t" { return true }
if ch == "u" { return true }
if ch == "v" { return true }
if ch == "w" { return true }
if ch == "x" { return true }
if ch == "y" { return true }
if ch == "z" { return true }
if ch == "A" { return true }
if ch == "B" { return true }
if ch == "C" { return true }
if ch == "D" { return true }
if ch == "E" { return true }
if ch == "F" { return true }
if ch == "G" { return true }
if ch == "H" { return true }
if ch == "I" { return true }
if ch == "J" { return true }
if ch == "K" { return true }
if ch == "L" { return true }
if ch == "M" { return true }
if ch == "N" { return true }
if ch == "O" { return true }
if ch == "P" { return true }
if ch == "Q" { return true }
if ch == "R" { return true }
if ch == "S" { return true }
if ch == "T" { return true }
if ch == "U" { return true }
if ch == "V" { return true }
if ch == "W" { return true }
if ch == "X" { return true }
if ch == "Y" { return true }
if ch == "Z" { return true }
false
}
fn is_alnum_or_underscore(ch: String) -> Bool {
if is_digit(ch) { return true }
if is_alpha(ch) { return true }
if ch == "_" { return true }
false
}
fn is_whitespace(ch: String) -> Bool {
if ch == " " { return true }
if ch == "\t" { return true }
if ch == "\n" { return true }
if ch == "\r" { return true }
false
}
fn make_tok(kind: String, value: String) -> Map<String, Any> {
{ "kind": kind, "value": value }
}
// Keyword lookup
fn keyword_kind(word: String) -> String {
if word == "let" { return "Let" }
if word == "fn" { return "Fn" }
if word == "type" { return "Type" }
if word == "enum" { return "Enum" }
if word == "match" { return "Match" }
if word == "return" { return "Return" }
if word == "if" { return "If" }
if word == "else" { return "Else" }
if word == "for" { return "For" }
if word == "in" { return "In" }
if word == "while" { return "While" }
if word == "import" { return "Import" }
if word == "from" { return "From" }
if word == "as" { return "As" }
if word == "with" { return "With" }
if word == "sealed" { return "Sealed" }
if word == "activate" { return "Activate" }
if word == "where" { return "Where" }
if word == "test" { return "Test" }
if word == "seed" { return "Seed" }
if word == "assert" { return "Assert" }
if word == "protocol" { return "Protocol" }
if word == "impl" { return "Impl" }
if word == "retry" { return "Retry" }
if word == "times" { return "Times" }
if word == "fallback" { return "Fallback" }
if word == "reason" { return "Reason" }
if word == "parallel" { return "Parallel" }
if word == "trace" { return "Trace" }
if word == "requires" { return "Requires" }
if word == "deploy" { return "Deploy" }
if word == "to" { return "To" }
if word == "via" { return "Via" }
if word == "target" { return "Target" }
if word == "true" { return "Bool" }
if word == "false" { return "Bool" }
if word == "cgi" { return "Cgi" }
if word == "manager" { return "Manager" }
if word == "engine" { return "Engine" }
if word == "accessor" { return "Accessor" }
if word == "vessel" { return "Vessel" }
""
}
// Scan helpers
// All scan helpers receive the chars list and total length.
// scan_digits advance i while chars[i] is a digit
// Returns { "text": ..., "pos": i }
fn scan_digits(chars: [String], start: Int, total: Int) -> Map<String, Any> {
let i = start
let text = ""
let running = true
while running {
if i >= total {
let running = false
} else {
let ch: String = native_list_get(chars, i)
if is_digit(ch) {
let text = text + ch
let i = i + 1
} else {
let running = false
}
}
}
{ "text": text, "pos": i }
}
// scan_ident advance i while chars[i] is alphanumeric or underscore
fn scan_ident(chars: [String], start: Int, total: Int) -> Map<String, Any> {
let i = start
let text = ""
let running = true
while running {
if i >= total {
let running = false
} else {
let ch: String = native_list_get(chars, i)
if is_alnum_or_underscore(ch) {
let text = text + ch
let i = i + 1
} else {
let running = false
}
}
}
{ "text": text, "pos": i }
}
// scan_string scan a quoted string literal, handling \" escapes.
// Starts AFTER the opening quote. Returns { "text": content, "pos": i_after_close }
fn scan_string(chars: [String], start: Int, total: Int) -> Map<String, Any> {
let i = start
let text = ""
let running = true
while running {
if i >= total {
let running = false
} else {
let ch: String = native_list_get(chars, i)
if ch == "\\" {
// escape: peek next char
let next_i = i + 1
if next_i < total {
let next_ch: String = native_list_get(chars, next_i)
if next_ch == "\"" {
let text = text + "\""
let i = next_i + 1
} else {
if next_ch == "n" {
let text = text + "\n"
let i = next_i + 1
} else {
if next_ch == "t" {
let text = text + "\t"
let i = next_i + 1
} else {
if next_ch == "r" {
let text = text + "\r"
let i = next_i + 1
} else {
if next_ch == "\\" {
let text = text + "\\"
let i = next_i + 1
} else {
let text = text + next_ch
let i = next_i + 1
}
}
}
}
}
} else {
let i = i + 1
}
} else {
if ch == "\"" {
let i = i + 1
let running = false
} else {
let text = text + ch
let i = i + 1
}
}
}
}
{ "text": text, "pos": i }
}
// Main lexer
fn lex(source: String) -> [Map<String, Any>] {
let chars: [String] = native_string_chars(source)
let total: Int = native_list_len(chars)
let tokens: [Map<String, Any>] = native_list_empty()
let i: Int = 0
while i < total {
let ch: String = native_list_get(chars, i)
// Skip whitespace
if is_whitespace(ch) {
let i = i + 1
} else {
// Line comments: //
if ch == "/" {
let next_i = i + 1
if next_i < total {
let next_ch: String = native_list_get(chars, next_i)
if next_ch == "/" {
// skip to end of line
let i = i + 2
let running2 = true
while running2 {
if i >= total {
let running2 = false
} else {
let lch: String = native_list_get(chars, i)
if lch == "\n" {
let running2 = false
} else {
let i = i + 1
}
}
}
} else {
let tokens = native_list_append(tokens, make_tok("Slash", "/"))
let i = i + 1
}
} else {
let tokens = native_list_append(tokens, make_tok("Slash", "/"))
let i = i + 1
}
} else {
// String literal
if ch == "\"" {
let result = scan_string(chars, i + 1, total)
let str_text: String = result["text"]
let new_pos: Int = result["pos"]
let tokens = native_list_append(tokens, make_tok("Str", str_text))
let i = new_pos
} else {
// Number literal
if is_digit(ch) {
let result = scan_digits(chars, i, total)
let num_text: String = result["text"]
let new_pos: Int = result["pos"]
// check for float (dot followed by digit)
if new_pos < total {
let dot_ch: String = native_list_get(chars, new_pos)
if dot_ch == "." {
let after_dot = new_pos + 1
if after_dot < total {
let after_dot_ch: String = native_list_get(chars, after_dot)
if is_digit(after_dot_ch) {
let frac_result = scan_digits(chars, after_dot, total)
let frac_text: String = frac_result["text"]
let frac_pos: Int = frac_result["pos"]
let tokens = native_list_append(tokens, make_tok("Float", num_text + "." + frac_text))
let i = frac_pos
} else {
let tokens = native_list_append(tokens, make_tok("Int", num_text))
let i = new_pos
}
} else {
let tokens = native_list_append(tokens, make_tok("Int", num_text))
let i = new_pos
}
} else {
let tokens = native_list_append(tokens, make_tok("Int", num_text))
let i = new_pos
}
} else {
let tokens = native_list_append(tokens, make_tok("Int", num_text))
let i = new_pos
}
} else {
// Identifier or keyword
if is_alpha(ch) || ch == "_" {
let result = scan_ident(chars, i, total)
let word: String = result["text"]
let new_pos: Int = result["pos"]
let kw = keyword_kind(word)
if kw == "" {
let tokens = native_list_append(tokens, make_tok("Ident", word))
} else {
let tokens = native_list_append(tokens, make_tok(kw, word))
}
let i = new_pos
} else {
// Multi-char and single-char operators/delimiters
let peek_i = i + 1
let peek_ch = ""
if peek_i < total {
let peek_ch: String = native_list_get(chars, peek_i)
}
if ch == "=" {
if peek_ch == "=" {
let tokens = native_list_append(tokens, make_tok("EqEq", "=="))
let i = i + 2
} else {
if peek_ch == ">" {
let tokens = native_list_append(tokens, make_tok("FatArrow", "=>"))
let i = i + 2
} else {
let tokens = native_list_append(tokens, make_tok("Eq", "="))
let i = i + 1
}
}
} else {
if ch == "!" {
if peek_ch == "=" {
let tokens = native_list_append(tokens, make_tok("NotEq", "!="))
let i = i + 2
} else {
let tokens = native_list_append(tokens, make_tok("Not", "!"))
let i = i + 1
}
} else {
if ch == "<" {
if peek_ch == "=" {
let tokens = native_list_append(tokens, make_tok("LtEq", "<="))
let i = i + 2
} else {
let tokens = native_list_append(tokens, make_tok("Lt", "<"))
let i = i + 1
}
} else {
if ch == ">" {
if peek_ch == "=" {
let tokens = native_list_append(tokens, make_tok("GtEq", ">="))
let i = i + 2
} else {
let tokens = native_list_append(tokens, make_tok("Gt", ">"))
let i = i + 1
}
} else {
if ch == "&" {
if peek_ch == "&" {
let tokens = native_list_append(tokens, make_tok("And", "&&"))
let i = i + 2
} else {
let i = i + 1
}
} else {
if ch == "|" {
if peek_ch == "|" {
let tokens = native_list_append(tokens, make_tok("Or", "||"))
let i = i + 2
} else {
if peek_ch == ">" {
let tokens = native_list_append(tokens, make_tok("PipeOp", "|>"))
let i = i + 2
} else {
let tokens = native_list_append(tokens, make_tok("Pipe", "|"))
let i = i + 1
}
}
} else {
if ch == "-" {
if peek_ch == ">" {
let tokens = native_list_append(tokens, make_tok("Arrow", "->"))
let i = i + 2
} else {
let tokens = native_list_append(tokens, make_tok("Minus", "-"))
let i = i + 1
}
} else {
if ch == ":" {
if peek_ch == ":" {
let tokens = native_list_append(tokens, make_tok("ColonColon", "::"))
let i = i + 2
} else {
let tokens = native_list_append(tokens, make_tok("Colon", ":"))
let i = i + 1
}
} else {
if ch == "+" {
let tokens = native_list_append(tokens, make_tok("Plus", "+"))
let i = i + 1
} else {
if ch == "*" {
let tokens = native_list_append(tokens, make_tok("Star", "*"))
let i = i + 1
} else {
if ch == "%" {
let tokens = native_list_append(tokens, make_tok("Percent", "%"))
let i = i + 1
} else {
if ch == "(" {
let tokens = native_list_append(tokens, make_tok("LParen", "("))
let i = i + 1
} else {
if ch == ")" {
let tokens = native_list_append(tokens, make_tok("RParen", ")"))
let i = i + 1
} else {
if ch == "{" {
let tokens = native_list_append(tokens, make_tok("LBrace", "{"))
let i = i + 1
} else {
if ch == "}" {
let tokens = native_list_append(tokens, make_tok("RBrace", "}"))
let i = i + 1
} else {
if ch == "[" {
let tokens = native_list_append(tokens, make_tok("LBracket", "["))
let i = i + 1
} else {
if ch == "]" {
let tokens = native_list_append(tokens, make_tok("RBracket", "]"))
let i = i + 1
} else {
if ch == "," {
let tokens = native_list_append(tokens, make_tok("Comma", ","))
let i = i + 1
} else {
if ch == "." {
let tokens = native_list_append(tokens, make_tok("Dot", "."))
let i = i + 1
} else {
if ch == ";" {
let tokens = native_list_append(tokens, make_tok("Semicolon", ";"))
let i = i + 1
} else {
if ch == "@" {
let tokens = native_list_append(tokens, make_tok("At", "@"))
let i = i + 1
} else {
if ch == "?" {
let tokens = native_list_append(tokens, make_tok("QuestionMark", "?"))
let i = i + 1
} else {
// unknown char skip
let i = i + 1
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
}
let tokens = native_list_append(tokens, make_tok("Eof", ""))
tokens
}
// parser.el el self-hosting recursive descent parser
//
// Consumes the token list produced by lexer.el and builds a list of AST
// statement maps. Each statement and expression is a Map<String, Any>.
//
// The cursor (integer position into the token list) is threaded through every
// parse function. Functions return { "node": <map>, "pos": <int> }.
//
// The token list is passed as a parameter to all parse functions.
// native_list_get is used to index into it without cloning.
//
// Entry point: fn parse(tokens: [Map<String, Any>]) -> [Map<String, Any>]
// Token access helpers
fn tok_at(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
native_list_get(tokens, pos)
}
fn tok_kind(tokens: [Map<String, Any>], pos: Int) -> String {
let t = native_list_get(tokens, pos)
t["kind"]
}
fn tok_value(tokens: [Map<String, Any>], pos: Int) -> String {
let t = native_list_get(tokens, pos)
t["value"]
}
fn expect(tokens: [Map<String, Any>], pos: Int, kind: String) -> Int {
let k = tok_kind(tokens, pos)
if k == kind {
return pos + 1
}
// On mismatch just advance; error recovery is best-effort
pos + 1
}
// Result helpers
fn make_result(node: Map<String, Any>, pos: Int) -> Map<String, Any> {
{ "node": node, "pos": pos }
}
// Type annotation parser
// Skips over a type annotation, returning the new position.
// Types can be: Ident, [Type], Map<K,V>, Type?, Type<Type,...>
fn skip_type(tokens: [Map<String, Any>], pos: Int) -> Int {
let k = tok_kind(tokens, pos)
// Array type: [Type]
if k == "LBracket" {
let p = pos + 1
let p = skip_type(tokens, p)
let p = expect(tokens, p, "RBracket")
return p
}
// Named type (possibly generic)
if k == "Ident" {
let p = pos + 1
let k2 = tok_kind(tokens, p)
if k2 == "Lt" {
// Generic params: skip until matching >
let p = p + 1
let depth = 1
let running = true
while running {
let kk = tok_kind(tokens, p)
if kk == "Eof" {
let running = false
} else {
if kk == "Lt" {
let depth = depth + 1
let p = p + 1
} else {
if kk == "Gt" {
let depth = depth - 1
let p = p + 1
if depth <= 0 {
let running = false
}
} else {
let p = p + 1
}
}
}
}
let k3 = tok_kind(tokens, p)
if k3 == "QuestionMark" {
let p = p + 1
}
return p
}
// Optional marker
if k2 == "QuestionMark" {
return p + 1
}
return p
}
pos + 1
}
// Parameter list
// Parses (name: Type, name: Type, ...) returns { "params": [...], "pos": ... }
fn parse_params(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let p = expect(tokens, pos, "LParen")
let params: [Map<String, Any>] = native_list_empty()
let running = true
while running {
let k = tok_kind(tokens, p)
if k == "RParen" {
let running = false
} else {
if k == "Eof" {
let running = false
} else {
// param name
let pname = tok_value(tokens, p)
let p = p + 1
let p = expect(tokens, p, "Colon")
let p = skip_type(tokens, p)
let param = { "name": pname }
let params = native_list_append(params, param)
let k2 = tok_kind(tokens, p)
if k2 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RParen")
{ "params": params, "pos": p }
}
// Expression parsing
fn parse_primary(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let k = tok_kind(tokens, pos)
let v = tok_value(tokens, pos)
// Integer literal
if k == "Int" {
return make_result({ "expr": "Int", "value": v }, pos + 1)
}
// Float literal
if k == "Float" {
return make_result({ "expr": "Float", "value": v }, pos + 1)
}
// String literal
if k == "Str" {
return make_result({ "expr": "Str", "value": v }, pos + 1)
}
// Bool literal
if k == "Bool" {
return make_result({ "expr": "Bool", "value": v }, pos + 1)
}
// Identifier
if k == "Ident" {
return make_result({ "expr": "Ident", "name": v }, pos + 1)
}
// Grouped expression
if k == "LParen" {
let r = parse_expr(tokens, pos + 1)
let node = r["node"]
let p = r["pos"]
let p = expect(tokens, p, "RParen")
return make_result(node, p)
}
// Array literal: [e1, e2, ...]
if k == "LBracket" {
let p = pos + 1
let elems: [Map<String, Any>] = native_list_empty()
let running = true
while running {
let k2 = tok_kind(tokens, p)
if k2 == "RBracket" {
let running = false
} else {
if k2 == "Eof" {
let running = false
} else {
let r = parse_expr(tokens, p)
let elem = r["node"]
let p = r["pos"]
let elems = native_list_append(elems, elem)
let k3 = tok_kind(tokens, p)
if k3 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RBracket")
return make_result({ "expr": "Array", "elems": elems }, p)
}
// Map literal: { "key": val, ... }
if k == "LBrace" {
let p = pos + 1
let pairs: [Map<String, Any>] = native_list_empty()
let running = true
while running {
let k2 = tok_kind(tokens, p)
if k2 == "RBrace" {
let running = false
} else {
if k2 == "Eof" {
let running = false
} else {
// key: Str token
let key = tok_value(tokens, p)
let p = p + 1
let p = expect(tokens, p, "Colon")
let r = parse_expr(tokens, p)
let val_node = r["node"]
let p = r["pos"]
let pair = { "key": key, "value": val_node }
let pairs = native_list_append(pairs, pair)
let k3 = tok_kind(tokens, p)
if k3 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RBrace")
return make_result({ "expr": "Map", "pairs": pairs }, p)
}
// if expression
if k == "If" {
let r = parse_if(tokens, pos)
return r
}
// match expression
if k == "Match" {
let r = parse_match(tokens, pos)
return r
}
// for expression (used as statement)
if k == "For" {
let r = parse_for_expr(tokens, pos)
return r
}
// Unary not
if k == "Not" {
let r = parse_primary(tokens, pos + 1)
let inner = r["node"]
let p = r["pos"]
return make_result({ "expr": "Not", "inner": inner }, p)
}
// Unary minus
if k == "Minus" {
let r = parse_primary(tokens, pos + 1)
let inner = r["node"]
let p = r["pos"]
return make_result({ "expr": "Neg", "inner": inner }, p)
}
// Fallback: skip unknown token
make_result({ "expr": "Nil" }, pos + 1)
}
fn parse_if(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let p = expect(tokens, pos, "If")
let r = parse_expr(tokens, p)
let cond = r["node"]
let p = r["pos"]
let r2 = parse_block(tokens, p)
let then_stmts = r2["stmts"]
let p = r2["pos"]
let has_else = false
let else_stmts: [Map<String, Any>] = native_list_empty()
let k2 = tok_kind(tokens, p)
if k2 == "Else" {
let p = p + 1
let k3 = tok_kind(tokens, p)
if k3 == "If" {
// else-if chain: parse as nested if
let r3 = parse_if(tokens, p)
let nested = r3["node"]
let p = r3["pos"]
let else_stmts = native_list_append(else_stmts, { "stmt": "Expr", "value": nested })
let has_else = true
} else {
let r3 = parse_block(tokens, p)
let else_stmts = r3["stmts"]
let p = r3["pos"]
let has_else = true
}
}
make_result({ "expr": "If", "cond": cond, "then": then_stmts, "else": else_stmts, "has_else": has_else }, p)
}
fn parse_match(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let p = expect(tokens, pos, "Match")
let r = parse_expr(tokens, p)
let subject = r["node"]
let p = r["pos"]
let p = expect(tokens, p, "LBrace")
let arms: [Map<String, Any>] = native_list_empty()
let running = true
while running {
let k = tok_kind(tokens, p)
if k == "RBrace" {
let running = false
} else {
if k == "Eof" {
let running = false
} else {
// parse pattern => body
let r2 = parse_pattern(tokens, p)
let pattern = r2["node"]
let p = r2["pos"]
let p = expect(tokens, p, "FatArrow")
let r3 = parse_expr(tokens, p)
let body = r3["node"]
let p = r3["pos"]
let arm = { "pattern": pattern, "body": body }
let arms = native_list_append(arms, arm)
let k2 = tok_kind(tokens, p)
if k2 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RBrace")
make_result({ "expr": "Match", "subject": subject, "arms": arms }, p)
}
fn parse_pattern(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let k = tok_kind(tokens, pos)
if k == "Ident" {
let v = tok_value(tokens, pos)
if v == "_" {
return make_result({ "pattern": "Wildcard" }, pos + 1)
}
return make_result({ "pattern": "Binding", "name": v }, pos + 1)
}
if k == "Int" {
return make_result({ "pattern": "LitInt", "value": tok_value(tokens, pos) }, pos + 1)
}
if k == "Str" {
return make_result({ "pattern": "LitStr", "value": tok_value(tokens, pos) }, pos + 1)
}
if k == "Bool" {
return make_result({ "pattern": "LitBool", "value": tok_value(tokens, pos) }, pos + 1)
}
// Wildcard _
make_result({ "pattern": "Wildcard" }, pos + 1)
}
fn parse_for_expr(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let p = expect(tokens, pos, "For")
let item_name = tok_value(tokens, p)
let p = p + 1
let p = expect(tokens, p, "In")
let r = parse_expr(tokens, p)
let list_expr = r["node"]
let p = r["pos"]
let r2 = parse_block(tokens, p)
let body = r2["stmts"]
let p = r2["pos"]
make_result({ "expr": "For", "item": item_name, "list": list_expr, "body": body }, p)
}
fn parse_block(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let p = expect(tokens, pos, "LBrace")
let stmts: [Map<String, Any>] = native_list_empty()
let running = true
while running {
let k = tok_kind(tokens, p)
if k == "RBrace" {
let running = false
} else {
if k == "Eof" {
let running = false
} else {
let r = parse_stmt(tokens, p)
let stmt = r["node"]
let p = r["pos"]
let stmts = native_list_append(stmts, stmt)
}
}
}
let p = expect(tokens, p, "RBrace")
{ "stmts": stmts, "pos": p }
}
// Postfix expressions (calls, field access, index)
fn parse_postfix(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let r = parse_primary(tokens, pos)
let node = r["node"]
let p = r["pos"]
let running = true
while running {
let k = tok_kind(tokens, p)
if k == "LParen" {
// function call
let p = p + 1
let args: [Map<String, Any>] = native_list_empty()
let run2 = true
while run2 {
let k2 = tok_kind(tokens, p)
if k2 == "RParen" {
let run2 = false
} else {
if k2 == "Eof" {
let run2 = false
} else {
let r2 = parse_expr(tokens, p)
let arg = r2["node"]
let p = r2["pos"]
let args = native_list_append(args, arg)
let k3 = tok_kind(tokens, p)
if k3 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RParen")
let node = { "expr": "Call", "func": node, "args": args }
} else {
if k == "Dot" {
let field = tok_value(tokens, p + 1)
let p = p + 2
let node = { "expr": "Field", "object": node, "field": field }
} else {
if k == "LBracket" {
let r2 = parse_expr(tokens, p + 1)
let idx = r2["node"]
let p = r2["pos"]
let p = expect(tokens, p, "RBracket")
let node = { "expr": "Index", "object": node, "index": idx }
} else {
if k == "QuestionMark" {
let p = p + 1
let node = { "expr": "Try", "inner": node }
} else {
let running = false
}
}
}
}
}
make_result(node, p)
}
// Binary expression precedence climbing
fn op_precedence(kind: String) -> Int {
if kind == "Or" { return 1 }
if kind == "And" { return 2 }
if kind == "EqEq" { return 3 }
if kind == "NotEq" { return 3 }
if kind == "Lt" { return 4 }
if kind == "Gt" { return 4 }
if kind == "LtEq" { return 4 }
if kind == "GtEq" { return 4 }
if kind == "Plus" { return 5 }
if kind == "Minus" { return 5 }
if kind == "Star" { return 6 }
if kind == "Slash" { return 6 }
0
}
fn is_binop(kind: String) -> Bool {
if kind == "Or" { return true }
if kind == "And" { return true }
if kind == "EqEq" { return true }
if kind == "NotEq" { return true }
if kind == "Lt" { return true }
if kind == "Gt" { return true }
if kind == "LtEq" { return true }
if kind == "GtEq" { return true }
if kind == "Plus" { return true }
if kind == "Minus" { return true }
if kind == "Star" { return true }
if kind == "Slash" { return true }
false
}
fn parse_binop(tokens: [Map<String, Any>], pos: Int, min_prec: Int) -> Map<String, Any> {
let r = parse_postfix(tokens, pos)
let left = r["node"]
let p = r["pos"]
let running = true
while running {
let k = tok_kind(tokens, p)
let prec = op_precedence(k)
if is_binop(k) {
if prec >= min_prec {
let op = k
let r2 = parse_binop(tokens, p + 1, prec + 1)
let right = r2["node"]
let p = r2["pos"]
let left = { "expr": "BinOp", "op": op, "left": left, "right": right }
} else {
let running = false
}
} else {
let running = false
}
}
make_result(left, p)
}
fn parse_expr(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
parse_binop(tokens, pos, 1)
}
// Statement parsing
fn parse_stmt(tokens: [Map<String, Any>], pos: Int) -> Map<String, Any> {
let k = tok_kind(tokens, pos)
// let binding
if k == "Let" {
let p = pos + 1
let name = tok_value(tokens, p)
let p = p + 1
let k2 = tok_kind(tokens, p)
// optional type annotation: name: Type
if k2 == "Colon" {
let p = p + 1
let p = skip_type(tokens, p)
}
let p = expect(tokens, p, "Eq")
let r = parse_expr(tokens, p)
let val = r["node"]
let p = r["pos"]
return make_result({ "stmt": "Let", "name": name, "value": val }, p)
}
// return statement
if k == "Return" {
let p = pos + 1
let k2 = tok_kind(tokens, p)
if k2 == "RBrace" {
return make_result({ "stmt": "Return", "value": { "expr": "Nil" } }, p)
}
if k2 == "Eof" {
return make_result({ "stmt": "Return", "value": { "expr": "Nil" } }, p)
}
let r = parse_expr(tokens, p)
let val = r["node"]
let p = r["pos"]
return make_result({ "stmt": "Return", "value": val }, p)
}
// fn definition
if k == "Fn" {
let p = pos + 1
let name = tok_value(tokens, p)
let p = p + 1
let r = parse_params(tokens, p)
let params = r["params"]
let p = r["pos"]
// return type annotation: -> Type. Capture the leading identifier
// so codegen can distinguish Void-returning functions from value-
// returning ones. Anything not "Void" is treated as a value type.
let ret_type = ""
let k2 = tok_kind(tokens, p)
if k2 == "Arrow" {
let p = p + 1
let kt = tok_kind(tokens, p)
if kt == "Ident" {
let ret_type = tok_value(tokens, p)
}
let p = skip_type(tokens, p)
}
let r2 = parse_block(tokens, p)
let body = r2["stmts"]
let p = r2["pos"]
return make_result({ "stmt": "FnDef", "name": name, "params": params, "body": body, "ret_type": ret_type }, p)
}
// type definition
if k == "Type" {
let p = pos + 1
let name = tok_value(tokens, p)
let p = p + 1
let p = expect(tokens, p, "LBrace")
let fields: [Map<String, Any>] = native_list_empty()
let running = true
while running {
let k2 = tok_kind(tokens, p)
if k2 == "RBrace" {
let running = false
} else {
if k2 == "Eof" {
let running = false
} else {
let fname = tok_value(tokens, p)
let p = p + 1
let p = expect(tokens, p, "Colon")
let p = skip_type(tokens, p)
let fields = native_list_append(fields, { "name": fname })
let k3 = tok_kind(tokens, p)
if k3 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RBrace")
return make_result({ "stmt": "TypeDef", "name": name, "fields": fields }, p)
}
// enum definition
if k == "Enum" {
let p = pos + 1
let name = tok_value(tokens, p)
let p = p + 1
let p = expect(tokens, p, "LBrace")
let variants: [Map<String, Any>] = native_list_empty()
let running = true
while running {
let k2 = tok_kind(tokens, p)
if k2 == "RBrace" {
let running = false
} else {
if k2 == "Eof" {
let running = false
} else {
let vname = tok_value(tokens, p)
let p = p + 1
let variants = native_list_append(variants, { "name": vname })
let k3 = tok_kind(tokens, p)
if k3 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RBrace")
return make_result({ "stmt": "EnumDef", "name": name, "variants": variants }, p)
}
// import statement
if k == "Import" {
let p = pos + 1
let path = tok_value(tokens, p)
let p = p + 1
return make_result({ "stmt": "Import", "path": path }, p)
}
// from ... import { ... }
if k == "From" {
let p = pos + 1
let module_name = tok_value(tokens, p)
let p = p + 1
// skip "import" keyword
let k2 = tok_kind(tokens, p)
if k2 == "Import" {
let p = p + 1
}
// skip { Name, ... }
let k3 = tok_kind(tokens, p)
if k3 == "LBrace" {
let p = p + 1
let running = true
while running {
let k4 = tok_kind(tokens, p)
if k4 == "RBrace" {
let running = false
} else {
if k4 == "Eof" {
let running = false
} else {
let p = p + 1
let k5 = tok_kind(tokens, p)
if k5 == "Comma" {
let p = p + 1
}
}
}
}
let p = expect(tokens, p, "RBrace")
}
return make_result({ "stmt": "Import", "path": module_name }, p)
}
// while loop
if k == "While" {
let p = pos + 1
let r = parse_expr(tokens, p)
let cond = r["node"]
let p = r["pos"]
let r2 = parse_block(tokens, p)
let body = r2["stmts"]
let p = r2["pos"]
return make_result({ "stmt": "While", "cond": cond, "body": body }, p)
}
// for loop
if k == "For" {
let p = pos + 1
let item_name = tok_value(tokens, p)
let p = p + 1
let p = expect(tokens, p, "In")
let r = parse_expr(tokens, p)
let list_expr = r["node"]
let p = r["pos"]
let r2 = parse_block(tokens, p)
let body = r2["stmts"]
let p = r2["pos"]
return make_result({ "stmt": "For", "item": item_name, "list": list_expr, "body": body }, p)
}
// @decorator skip and parse next stmt
if k == "At" {
let p = pos + 1
// skip decorator name
let p = p + 1
return parse_stmt(tokens, p)
}
// bare expression or if/match statement
let r = parse_expr(tokens, pos)
let val = r["node"]
let p = r["pos"]
make_result({ "stmt": "Expr", "value": val }, p)
}
// Top-level parse
fn parse(tokens: [Map<String, Any>]) -> [Map<String, Any>] {
let total: Int = native_list_len(tokens)
let stmts: [Map<String, Any>] = native_list_empty()
let pos: Int = 0
let running = true
while running {
if pos >= total {
let running = false
} else {
let k = tok_kind(tokens, pos)
if k == "Eof" {
let running = false
} else {
let r = parse_stmt(tokens, pos)
let stmt = r["node"]
let new_pos: Int = r["pos"]
let stmts = native_list_append(stmts, stmt)
// Guard against infinite loops if pos didn't advance, force it
if new_pos <= pos {
let pos = pos + 1
} else {
let pos = new_pos
}
}
}
}
stmts
}
// codegen.el El compiler C source code generator
//
// Input: list of AST statement maps (from parser.el)
// Output: C source printed to stdout (streamed, one line at a time)
//
// Each El program compiles to a single .c file that #includes el_runtime.h.
// Functions map directly to C functions; top-level statements become main().
//
// Entry point: fn codegen(stmts: [Map<String, Any>], source: String) -> String
// Returns "" output goes to stdout via println().
//
// Streaming output avoids O(n²) string concatenation: each emitted line is
// printed immediately rather than appended to a growing string.
// String helpers
// Escape a C string literal (double-quotes and backslashes).
fn c_escape(s: String) -> String {
let chars: [String] = native_string_chars(s)
let total: Int = native_list_len(chars)
let out = ""
let i = 0
while i < total {
let ch: String = native_list_get(chars, i)
if ch == "\"" {
let out = out + "\\\""
} else {
if ch == "\\" {
let out = out + "\\\\"
} else {
if ch == "\n" {
let out = out + "\\n"
} else {
if ch == "\r" {
let out = out + "\\r"
} else {
if ch == "\t" {
let out = out + "\\t"
} else {
let out = out + ch
}
}
}
}
}
let i = i + 1
}
out
}
fn c_str_lit(s: String) -> String {
"\"" + c_escape(s) + "\""
}
// Type mapping
fn el_type_to_c(type_str: String) -> String {
if type_str == "String" { return "const char*" }
if type_str == "Int" { return "int64_t" }
if type_str == "Bool" { return "int" }
if type_str == "Float" { return "double" }
if type_str == "Void" { return "void" }
if type_str == "void" { return "void" }
"void*"
}
// Code emission
//
// emit_line/emit_blank stream output directly via println.
// This avoids building a large string in memory.
fn emit_line(line: String) -> Void {
println(line)
}
fn emit_blank() -> Void {
println("")
}
// Operator helpers
fn binop_to_c(op: String) -> String {
if op == "Plus" { return "+" }
if op == "Minus" { return "-" }
if op == "Star" { return "*" }
if op == "Slash" { return "/" }
if op == "EqEq" { return "==" }
if op == "NotEq" { return "!=" }
if op == "Lt" { return "<" }
if op == "Gt" { return ">" }
if op == "LtEq" { return "<=" }
if op == "GtEq" { return ">=" }
if op == "And" { return "&&" }
if op == "Or" { return "||" }
op
}
// Expression codegen
//
// cg_expr returns a C expression string (not a statement).
fn cg_expr(expr: Map<String, Any>) -> String {
let kind: String = expr["expr"]
if kind == "Int" {
let v: String = expr["value"]
return v
}
if kind == "Float" {
let v: String = expr["value"]
return v
}
if kind == "Str" {
let v: String = expr["value"]
return "EL_STR(" + c_str_lit(v) + ")"
}
if kind == "Bool" {
let v: String = expr["value"]
if v == "true" { return "1" }
return "0"
}
if kind == "Nil" {
return "EL_NULL"
}
if kind == "Ident" {
let name: String = expr["name"]
return name
}
if kind == "Not" {
let inner = expr["inner"]
let inner_c: String = cg_expr(inner)
return "!" + inner_c
}
if kind == "Neg" {
let inner = expr["inner"]
let inner_c: String = cg_expr(inner)
return "(-" + inner_c + ")"
}
if kind == "BinOp" {
let op: String = expr["op"]
let left = expr["left"]
let right = expr["right"]
let left_c: String = cg_expr(left)
let right_c: String = cg_expr(right)
let left_kind: String = left["expr"]
let right_kind: String = right["expr"]
if op == "Plus" {
// If either side is a string literal, always concat
if left_kind == "Str" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
if right_kind == "Str" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
// If either side is an integer literal, this is arithmetic (not string concat)
if left_kind == "Int" {
let op_c: String = binop_to_c(op)
return "(" + left_c + " " + op_c + " " + right_c + ")"
}
if right_kind == "Int" {
let op_c: String = binop_to_c(op)
return "(" + left_c + " " + op_c + " " + right_c + ")"
}
if left_kind == "Call" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
if right_kind == "Call" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
if left_kind == "BinOp" {
let left_op: String = left["op"]
if left_op == "Plus" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
}
if right_kind == "BinOp" {
let right_op: String = right["op"]
if right_op == "Plus" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
}
// Ident + Ident or Ident + unknown assume string concat
// (This is the ambiguous case: El uses + for both string and integer ops)
if left_kind == "Ident" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
if right_kind == "Ident" {
return "el_str_concat(" + left_c + ", " + right_c + ")"
}
}
// String equality: use str_eq() when either side is a string literal or ident.
// Use plain == when comparing integer literals.
if op == "EqEq" {
// Integer literal on either side arithmetic comparison
if left_kind == "Int" {
return "(" + left_c + " == " + right_c + ")"
}
if right_kind == "Int" {
return "(" + left_c + " == " + right_c + ")"
}
if left_kind == "Bool" {
return "(" + left_c + " == " + right_c + ")"
}
if right_kind == "Bool" {
return "(" + left_c + " == " + right_c + ")"
}
if left_kind == "Str" {
return "str_eq(" + left_c + ", " + right_c + ")"
}
if right_kind == "Str" {
return "str_eq(" + left_c + ", " + right_c + ")"
}
if left_kind == "Ident" {
return "str_eq(" + left_c + ", " + right_c + ")"
}
if right_kind == "Ident" {
return "str_eq(" + left_c + ", " + right_c + ")"
}
if left_kind == "Call" {
return "str_eq(" + left_c + ", " + right_c + ")"
}
if right_kind == "Call" {
return "str_eq(" + left_c + ", " + right_c + ")"
}
}
if op == "NotEq" {
if left_kind == "Int" {
return "(" + left_c + " != " + right_c + ")"
}
if right_kind == "Int" {
return "(" + left_c + " != " + right_c + ")"
}
if left_kind == "Bool" {
return "(" + left_c + " != " + right_c + ")"
}
if right_kind == "Bool" {
return "(" + left_c + " != " + right_c + ")"
}
if left_kind == "Str" {
return "!str_eq(" + left_c + ", " + right_c + ")"
}
if right_kind == "Str" {
return "!str_eq(" + left_c + ", " + right_c + ")"
}
if left_kind == "Ident" {
return "!str_eq(" + left_c + ", " + right_c + ")"
}
if right_kind == "Ident" {
return "!str_eq(" + left_c + ", " + right_c + ")"
}
if left_kind == "Call" {
return "!str_eq(" + left_c + ", " + right_c + ")"
}
if right_kind == "Call" {
return "!str_eq(" + left_c + ", " + right_c + ")"
}
}
let op_c: String = binop_to_c(op)
return "(" + left_c + " " + op_c + " " + right_c + ")"
}
if kind == "Call" {
let func = expr["func"]
let args = expr["args"]
let arity: Int = native_list_len(args)
let func_kind: String = func["expr"]
let args_c = ""
let i = 0
while i < arity {
let arg = native_list_get(args, i)
let arg_c: String = cg_expr(arg)
if i > 0 {
let args_c = args_c + ", "
}
let args_c = args_c + arg_c
let i = i + 1
}
if func_kind == "Ident" {
let fn_name: String = func["name"]
return fn_name + "(" + args_c + ")"
}
if func_kind == "Field" {
let obj = func["object"]
let field: String = func["field"]
let obj_c: String = cg_expr(obj)
if arity > 0 {
return field + "(" + obj_c + ", " + args_c + ")"
}
return field + "(" + obj_c + ")"
}
let fn_c: String = cg_expr(func)
return fn_c + "(" + args_c + ")"
}
if kind == "Field" {
let obj = expr["object"]
let field: String = expr["field"]
let obj_c: String = cg_expr(obj)
return "el_get_field(" + obj_c + ", " + c_str_lit(field) + ")"
}
if kind == "Index" {
// El programs use `t["field"]` for map access and `arr[i]` for
// list access. The parser emits the same Index node for both.
// Dispatch at codegen time on the index expression kind: string-
// literal index map field access (`el_get_field`); anything
// else list element access (`el_list_get`).
let obj = expr["object"]
let idx = expr["index"]
let obj_c: String = cg_expr(obj)
let idx_c: String = cg_expr(idx)
let idx_kind: String = idx["expr"]
if str_eq(idx_kind, "Str") {
return "el_get_field(" + obj_c + ", " + idx_c + ")"
}
return "el_list_get(" + obj_c + ", " + idx_c + ")"
}
if kind == "Array" {
let elems = expr["elems"]
let n: Int = native_list_len(elems)
let items = ""
let i = 0
while i < n {
let elem = native_list_get(elems, i)
let elem_c: String = cg_expr(elem)
if i > 0 {
let items = items + ", "
}
let items = items + elem_c
let i = i + 1
}
return "el_list_new(" + native_int_to_str(n) + ", " + items + ")"
}
if kind == "Map" {
let pairs = expr["pairs"]
let n: Int = native_list_len(pairs)
let items = ""
let i = 0
while i < n {
let pair = native_list_get(pairs, i)
let key: String = pair["key"]
let val = pair["value"]
let val_c: String = cg_expr(val)
if i > 0 {
let items = items + ", "
}
let items = items + c_str_lit(key) + ", " + val_c
let i = i + 1
}
return "el_map_new(" + native_int_to_str(n) + ", " + items + ")"
}
if kind == "Try" {
let inner = expr["inner"]
return cg_expr(inner)
}
if kind == "If" {
let cond = expr["cond"]
let cond_c: String = cg_expr(cond)
return "/* if-expr */ ((" + cond_c + ") ? (el_val_t)1 : (el_val_t)0)"
}
"EL_NULL"
}
// Variable scope tracking
//
// El allows `let x = expr` to both declare and reassign x in the same scope.
// C doesn't allow redeclaring the same name in the same block.
// We track declared names in a list and emit `x = expr` (no type prefix)
// when x is already declared. The declared list is passed through all
// statement emitters.
fn list_contains(lst: [String], s: String) -> Bool {
let n: Int = native_list_len(lst)
let i = 0
while i < n {
let item: String = native_list_get(lst, i)
if item == s { return true }
let i = i + 1
}
false
}
// Statement codegen
//
// cg_stmt emits C lines via println. declared is a list of already-declared
// variable names in the current C scope; returns updated declared list.
fn cg_stmt(stmt: Map<String, Any>, indent: String, declared: [String]) -> [String] {
let kind: String = stmt["stmt"]
if kind == "Let" {
let name: String = stmt["name"]
let val = stmt["value"]
let val_c: String = cg_expr(val)
if list_contains(declared, name) {
emit_line(indent + name + " = " + val_c + ";")
return declared
} else {
emit_line(indent + "el_val_t " + name + " = " + val_c + ";")
return native_list_append(declared, name)
}
}
if kind == "Return" {
let val = stmt["value"]
let val_kind: String = val["expr"]
if val_kind == "Nil" {
emit_line(indent + "return 0;")
} else {
let val_c: String = cg_expr(val)
emit_line(indent + "return " + val_c + ";")
}
return declared
}
if kind == "Expr" {
let val = stmt["value"]
let val_kind: String = val["expr"]
if val_kind == "If" {
cg_if_stmt(val, indent, declared)
return declared
}
if val_kind == "For" {
cg_for_stmt(val, indent, declared)
return declared
}
let val_c: String = cg_expr(val)
emit_line(indent + val_c + ";")
return declared
}
if kind == "While" {
let cond = stmt["cond"]
let body = stmt["body"]
let cond_c: String = cg_expr(cond)
let cond_c = strip_outer_parens(cond_c)
emit_line(indent + "while (" + cond_c + ") {")
cg_stmts(body, indent + " ", declared)
emit_line(indent + "}")
return declared
}
if kind == "For" {
let item: String = stmt["item"]
let list_expr = stmt["list"]
let body = stmt["body"]
cg_for_body(item, list_expr, body, indent, declared)
return declared
}
if kind == "FnDef" { return declared }
if kind == "TypeDef" { return declared }
if kind == "EnumDef" { return declared }
if kind == "Import" { return declared }
declared
}
// Strip a single layer of surrounding parentheses from a C expression string.
fn strip_outer_parens(s: String) -> String {
let chars: [String] = native_string_chars(s)
let n: Int = native_list_len(chars)
if n < 2 { return s }
let first: String = native_list_get(chars, 0)
let last: String = native_list_get(chars, n - 1)
if first == "(" {
if last == ")" {
let depth = 1
let i = 1
let balanced = true
while i < n - 1 {
let ch: String = native_list_get(chars, i)
if ch == "(" {
let depth = depth + 1
}
if ch == ")" {
let depth = depth - 1
if depth == 0 {
let balanced = false
let i = n
}
}
let i = i + 1
}
if balanced {
let inner = ""
let j = 1
while j < n - 1 {
let ch: String = native_list_get(chars, j)
let inner = inner + ch
let j = j + 1
}
return inner
}
}
}
s
}
fn cg_if_stmt(expr: Map<String, Any>, indent: String, declared: [String]) -> Void {
let cond = expr["cond"]
let then_stmts = expr["then"]
let else_stmts = expr["else"]
let has_else: Bool = expr["has_else"]
let cond_c: String = cg_expr(cond)
let cond_c = strip_outer_parens(cond_c)
emit_line(indent + "if (" + cond_c + ") {")
cg_stmts(then_stmts, indent + " ", declared)
if has_else {
emit_line(indent + "} else {")
cg_stmts(else_stmts, indent + " ", declared)
}
emit_line(indent + "}")
}
fn cg_for_body(item: String, list_expr: Map<String, Any>, body: [Map<String, Any>], indent: String, declared: [String]) -> Void {
let list_c: String = cg_expr(list_expr)
let idx = "_el_i"
let list_tmp = "_el_lst"
let len_tmp = "_el_len"
emit_line(indent + "{")
emit_line(indent + " el_val_t " + list_tmp + " = " + list_c + ";")
emit_line(indent + " el_val_t " + len_tmp + " = el_list_len(" + list_tmp + ");")
emit_line(indent + " for (el_val_t " + idx + " = 0; " + idx + " < " + len_tmp + "; " + idx + "++) {")
emit_line(indent + " el_val_t " + item + " = el_list_get(" + list_tmp + ", " + idx + ");")
cg_stmts(body, indent + " ", declared)
emit_line(indent + " }")
emit_line(indent + "}")
}
fn cg_for_stmt(expr: Map<String, Any>, indent: String, declared: [String]) -> Void {
let item: String = expr["item"]
let list_expr = expr["list"]
let body = expr["body"]
cg_for_body(item, list_expr, body, indent, declared)
}
fn cg_stmts(stmts: [Map<String, Any>], indent: String, declared: [String]) -> [String] {
let n: Int = native_list_len(stmts)
let i = 0
let decl = declared
while i < n {
let stmt = native_list_get(stmts, i)
let decl = cg_stmt(stmt, indent, decl)
let i = i + 1
}
decl
}
// Function declaration codegen
fn param_decl(param: Map<String, Any>, idx: Int) -> String {
let name: String = param["name"]
"el_val_t " + name
}
fn params_to_c(params: [Map<String, Any>]) -> String {
let n: Int = native_list_len(params)
if n == 0 { return "void" }
let out = ""
let i = 0
while i < n {
let param = native_list_get(params, i)
let decl: String = param_decl(param, i)
if i > 0 {
let out = out + ", "
}
let out = out + decl
let i = i + 1
}
out
}
// Transform a function body so that an implicit-return final expression
// becomes an explicit Return. El allows the last expression in a function
// body to be the return value (e.g. `fn lex(s) { ... tokens }` returns
// `tokens`). Without this transform, the codegen emits the bare expression
// and falls through to the trailing `return 0;`, losing the value.
//
// Rules: a body ending in a bare Expr whose inner expr is NOT a control-
// flow construct (If/For) is rewritten so that final Expr becomes a
// Return statement carrying the same value. Bodies whose final statement
// is already a Return, While, For, or a non-value-producing form pass
// through unchanged.
fn transform_implicit_return(body: [Map<String, Any>]) -> [Map<String, Any>] {
let n: Int = native_list_len(body)
if n == 0 { return body }
let last: Map<String, Any> = native_list_get(body, n - 1)
let last_kind: String = last["stmt"]
if last_kind == "Expr" {
let val = last["value"]
let val_kind: String = val["expr"]
// Skip control-flow expressions used as statements
if val_kind == "If" { return body }
if val_kind == "For" { return body }
// Replace the last bare Expr with a Return carrying the same value
let new_body: [Map<String, Any>] = native_list_empty()
let i = 0
while i < n - 1 {
let new_body = native_list_append(new_body, native_list_get(body, i))
let i = i + 1
}
let return_stmt: Map<String, Any> = { "stmt": "Return", "value": val }
let new_body = native_list_append(new_body, return_stmt)
return new_body
}
body
}
fn cg_fn(stmt: Map<String, Any>) -> Void {
let fn_name: String = stmt["name"]
// Skip El's `fn main()` C provides its own main() for top-level stmts
// and a duplicate `el_val_t main(void)` would collide with it.
if fn_name == "main" { return }
let params = stmt["params"]
let body = stmt["body"]
let ret_type: String = stmt["ret_type"]
let params_c: String = params_to_c(params)
emit_line("el_val_t " + fn_name + "(" + params_c + ") {")
// Seed declared with parameter names so reassignment works
let decl = native_list_empty()
let np: Int = native_list_len(params)
let pi = 0
while pi < np {
let param = native_list_get(params, pi)
let pname: String = param["name"]
let decl = native_list_append(decl, pname)
let pi = pi + 1
}
// Lift the final bare expression into an explicit return so implicit
// returns ("fn lex(s) { ... tokens }") actually return their value.
// Void-returning functions skip this wrapping `println(x)` in
// `return ` is a C type error.
let body_xformed = body
if !str_eq(ret_type, "Void") {
let body_xformed = transform_implicit_return(body)
}
cg_stmts(body_xformed, " ", decl)
emit_line(" return 0;")
emit_line("}")
emit_blank()
}
// Top-level codegen
fn is_fndef(stmt: Map<String, Any>) -> Bool {
let kind: String = stmt["stmt"]
if kind == "FnDef" { return true }
false
}
fn is_top_level_decl(stmt: Map<String, Any>) -> Bool {
let kind: String = stmt["stmt"]
if kind == "TypeDef" { return true }
if kind == "EnumDef" { return true }
if kind == "Import" { return true }
false
}
// Entry point
fn codegen(stmts: [Map<String, Any>], source: String) -> String {
// Preamble
emit_line("#include <stdint.h>")
emit_line("#include <stdlib.h>")
emit_line("#include \"el_runtime.h\"")
emit_blank()
// Forward declarations (skip `main` C provides its own)
let n: Int = native_list_len(stmts)
let i = 0
while i < n {
let stmt = native_list_get(stmts, i)
let kind: String = stmt["stmt"]
if kind == "FnDef" {
let fn_name: String = stmt["name"]
if !str_eq(fn_name, "main") {
let params = stmt["params"]
let params_c: String = params_to_c(params)
emit_line("el_val_t " + fn_name + "(" + params_c + ");")
}
}
let i = i + 1
}
emit_blank()
// Function definitions
let i = 0
while i < n {
let stmt = native_list_get(stmts, i)
if is_fndef(stmt) {
cg_fn(stmt)
}
let i = i + 1
}
// main()
emit_line("int main(int argc, char** argv) {")
emit_line(" el_runtime_init_args(argc, argv);")
let main_decl = native_list_empty()
let i = 0
while i < n {
let stmt = native_list_get(stmts, i)
if is_fndef(stmt) {
// skip
} else {
if is_top_level_decl(stmt) {
// skip
} else {
let main_decl = cg_stmt(stmt, " ", main_decl)
}
}
let i = i + 1
}
emit_line(" return 0;")
emit_line("}")
emit_blank()
// Return empty string output was streamed via println
""
}
// compiler.el el self-hosting compiler pipeline
//
// Wires lexer -> parser -> codegen into a single compile() function.
// This is the bootstrap entry point: compiled once by the Rust el-compiler,
// then self-hosted from that point forward.
//
// The returned string is C source code. Compile the output with:
// cc -o <prog> <prog>.c el_runtime.c
// compile full pipeline: source string -> C source string
fn compile(source: String) -> String {
let tokens: [Map<String, Any>] = lex(source)
let stmts: [Map<String, Any>] = parse(tokens)
codegen(stmts, source)
}
// main CLI entry point for self-hosted compilation.
//
// Called by: elc <source.el> <output.c>
//
// Reads El source from args()[0], compiles it to C source, and writes the
// result to args()[1]. Then run:
// cc -o <prog> <output.c> el_runtime.c
// CLI driver equivalent to: elc <source.el>
let _argv: [String] = args()
let _src_path: String = native_list_get(_argv, 0)
let _source: String = fs_read(_src_path)
compile(_source)