test "name" { ... } blocks were not recognized by the self-hosted
compiler. The body { } was parsed as a Map literal, creating a huge
AST with O(n²) string concatenation in the toplevel_exec_stmts loop
(which had no arena scope). A 272-line test file would consume 400MB+
and a 720-line file importing the full compiler source caused 150GB
usage and crashed the machine.
Two fixes:
1. Skip Test tokens in codegen_streaming before parse_one() —
advance past "name" and skip_to_rbrace on the body block.
Test blocks are never compiled; self-hosted compiler has no test runner.
2. Add per-statement arena scope to toplevel_exec_stmts emission loop,
matching the el_main_body loop. Frees intermediate strings after
each statement to prevent O(n²) accumulation from any unrecognized
construct that reaches that path.
Result: test_string.el (272 lines, 27 test blocks): 0MB peak (was 400MB+).
test_compiler.el (720 lines + 8728 imported): 15MB peak (was 150GB).
- Flat token list: lexer emits [kind0, val0, kind1, val1, ...] instead of [{kind,val}, ...]
Eliminates per-token ElMap allocation (~112B × N tokens)
- str_char_code hot loop: char classification via Int codes, no strdup per char
- Batch c_escape: str_slice clean runs instead of char-at per byte
- Parser updated to use tok_at/tok_kind/tok_value stride-2 accessors
Combines two orthogonal optimizations:
1. c_escape batching (from alpha): ASCII runs emitted as str_slice segments instead
of one str_char_at string per byte. O(N) allocs → O(K) where K = special chars.
2. scan_interp_string batching (from beta): char dispatch via str_char_code (Int)
+ clean_start tracking to flush plain runs as str_slice. Eliminates per-char
string allocations in the string-literal scanning hot path.
Result on web/src/main.el: 14.5MB -> 13.4MB peak RSS (-7.6%).
Self-hosting: PASS.
Will Anderson