IR deliberately allows broad Unicode glyphs to act as user-definable infix operators. SPECIAL is therefore not supposed to be narrowed to only a small approved set.
The invariant is precedence: glyphs selected for built-in syntax must be recognized by their explicit lexer rules before the generic Unicode infix fallback can claim them.
The immediate case is equality. ≟ must tokenize as the existing equality token/semantics, not as a generic SPECIAL operator. The ASCII aliases ?=, =?, ?=?, and ¿=? should likewise resolve to the same equality operation.
Acceptance criteria:
≟ tokenizes as equality, never generic SPECIAL.?=, =?, ?=?, and ¿=? are tested as aliases for ≟.- Existing reserved Unicode syntax such as assignment arrows continues to beat the generic infix fallback.
- Broad user-definable Unicode infix behavior remains available for unreserved glyphs.
- Regression tests include at least one unreserved Unicode infix glyph proving that fallback still works.
- Code-point literals used by these lexer/tests carry the rendered glyph beside them, and tests verify important code-point↔glyph pairs (for example U+03C0 really renders as
π) so the comments cannot silently drift from what the code prints.
This is a lexer-priority invariant: explicit syntax first, generic Unicode infix fallback second.
IR deliberately allows broad Unicode glyphs to act as user-definable infix operators.
SPECIALis therefore not supposed to be narrowed to only a small approved set.The invariant is precedence: glyphs selected for built-in syntax must be recognized by their explicit lexer rules before the generic Unicode infix fallback can claim them.
The immediate case is equality.
≟must tokenize as the existing equality token/semantics, not as a genericSPECIALoperator. The ASCII aliases?=,=?,?=?, and¿=?should likewise resolve to the same equality operation.Acceptance criteria:
≟tokenizes as equality, never genericSPECIAL.?=,=?,?=?, and¿=?are tested as aliases for≟.π) so the comments cannot silently drift from what the code prints.This is a lexer-priority invariant: explicit syntax first, generic Unicode infix fallback second.