PEGO
M120: Unboxed Text Comparisons
Comparing two text results through generic interface values can allocate
string headers. Native string equality avoids those boxes.
Mechanism and Invariants
Eligible equality/inequality expressions extract text and compare strings
directly while preserving operand errors. VMs use ETEXTCHK/ETEXTEQ
expression instructions; generators emit native comparisons. This changes
comparison plumbing, not substring ownership or arbitrary string-valued action
results.
Scope and State
Default eligible comparisons in closure, both VMs, generated Go Node/typed Go and TypeScript. JavaScript strings do not have Go interface-header allocations, though its emitter also uses native string comparison.
Reference Control
No isolated same-source text-boxing control exists. Literal-text disjunction specialization is independently controlled.
Evidence and Implementation
Record 036 measures XML about 19k to 1.1k allocations in closure/generated Go; 044 ports the shape to VMs alongside concat fusion. TypeScript has no corresponding Go-allocation claim. Record 102 measured a text struct field read that named node types have since made unnecessary.
Evidence records: 036, 044, 102.
Source owners: text equality evaluator,
ETEXTCHK and ETEXTEQ, native text comparison instructions, text comparison emission, TypeScript text comparison emission.
The comparison policy distinguishes same-source controls, historical changes and full checkpoints.