39 lines
1.2 KiB
Markdown
39 lines
1.2 KiB
Markdown
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# Nyash Grammar (Stage‑2 EBNF)
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Status: Fixed for Phase 15 Stage‑2. Parser implementations (Rust/Python/Nyash selfhost) should conform to this subset.
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program := stmt* EOF
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stmt := 'return' expr
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| 'local' IDENT '=' expr
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| 'if' expr block ('else' block)?
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| 'loop' '('? expr ')' ? block
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| expr ; expression statement
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block := '{' stmt* '}'
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expr := logic
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logic := compare (('&&' | '||') compare)*
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compare := sum (( '==' | '!=' | '<' | '>' | '<=' | '>=' ) sum)?
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sum := term (('+' | '-') term)*
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term := unary (('*' | '/') unary)*
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unary := '-' unary | factor
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factor := INT
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| STRING
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| IDENT call_tail*
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| '(' expr ')'
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| 'new' IDENT '(' args? ')'
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call_tail := '.' IDENT '(' args? ')' ; method
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| '(' args? ')' ; function call
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args := expr (',' expr)*
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Notes
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- ASI: Newline is the primary statement separator. Do not insert a semicolon between a closed block and a following 'else'.
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- Short-circuit: '&&' and '||' must not evaluate the RHS when not needed.
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- Unary minus has higher precedence than '*' and '/'.
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- IDENT names consist of [A-Za-z_][A-Za-z0-9_]*
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