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authorCliff Click <cliffc@acm.org>2026-10-07 09:53:15 -0700
committerCliff Click <cliffc@acm.org>2026-10-07 09:53:15 -0700
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treebbeab7de6ac8b556911d117989ab4bbc0324ecb5 /chapter24/docs/24-grammar.md
parent863a6ed0ad723e06c76f392d4fb3a5f6bd22863c (diff)
downloadSimple-pr262-doc-followups.tar.gz
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Pick up japanese transaltionpr262-doc-followups
A bunch of minor README fixes, missing TOC, grammer cleanup
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+# Grammar for Chapter 24
+
+English | [日本語](24-grammar.ja.md)
+
+```antlrv4
+grammar SimpleLanguage;
+
+// Name lookup, assignable operands, type compatibility, and access permissions
+// are checked by the compiler in addition to these syntax rules.
+program : statement* EOF ;
+
+block : '{' statement* '}' ;
+
+statement
+ : block
+ | returnStatement
+ | ifStatement
+ | whileStatement
+ | forStatement
+ | breakStatement
+ | continueStatement
+ | structDeclaration
+ | declaration ';'
+ | assignment ';'
+ | ';'
+ ;
+
+returnStatement : 'return' assignment ';' ;
+ifStatement : 'if' '(' assignment ')' statement ('else' statement)? ;
+whileStatement : 'while' '(' assignment ')' statement ;
+breakStatement : 'break' ';' ;
+continueStatement : 'continue' ';' ;
+
+forStatement
+ : 'for' '(' (declaration | assignment)? ';' assignment? ';' assignment? ')' statement
+ ;
+
+structDeclaration : 'struct' IDENTIFIER '{' structMember* '}' ';' ;
+structMember : methodDeclaration | statement ;
+
+// A method is an ordinary fixed function binding in a struct definition.
+// The compiler supplies self; it is not written in parameterList.
+// The general declaration rule also admits explicitly typed function fields.
+methodDeclaration : 'val' bindingModifier? IDENTIFIER '=' functionExpression ';' ;
+
+declaration : declarationType binding (',' binding)* ;
+declarationType : type | 'var' | 'val' ;
+binding : bindingModifier? IDENTIFIER ('=' initializer)? ;
+bindingModifier : '!' | '~' ;
+// A declaration initializer consisting of the string "C" declares an extern
+// symbol. Ordinary strings elsewhere are array-valued expressions.
+initializer : assignment ;
+
+// The prefix qualifies the named struct reference, not an enclosing array.
+// Each [] / [~] suffix qualifies its own array layer. ? requires a reference.
+type
+ : functionType
+ | primitiveType typeSuffix*
+ | accessModifier? typeName typeSuffix*
+ ;
+accessModifier : '!' | '~' ;
+typeSuffix : '?' | '[]' | '[~]' ;
+typeName : IDENTIFIER ('.' IDENTIFIER)* ;
+
+primitiveType
+ : 'int' | 'i8' | 'i16' | 'i32' | 'i64'
+ | 'u1' | 'u8' | 'u16' | 'u32' | 'byte' | 'bool'
+ | 'flt' | 'f32' | 'f64'
+ ;
+
+assignment : expression (assignmentOperator assignment)? ;
+assignmentOperator
+ : '=' | '+=' | '-=' | '*=' | '/=' | '&=' | '|=' | '^='
+ | '<<=' | '>>=' | '>>>='
+ ;
+
+expression : logicalExpression ('?' assignment (':' assignment)?)? ;
+
+// Both logical operators short-circuit and associate to the right here.
+logicalExpression : bitwiseExpression (('&&' | '||') logicalExpression)? ;
+
+bitwiseExpression
+ : equalityExpression (('&' | '|' | '^') equalityExpression)*
+ ;
+
+equalityExpression : comparisonExpression (('==' | '!=') comparisonExpression)* ;
+
+// Chained comparisons test adjacent operands and short-circuit. A chain must
+// keep its direction; equality has lower precedence and does not join a chain.
+comparisonExpression
+ : shiftExpression
+ ( (('<' | '<=') shiftExpression)+ | (('>' | '>=') shiftExpression)+ )?
+ ;
+
+shiftExpression
+ : additiveExpression (('<<' | '>>' | '>>>') additiveExpression)*
+ ;
+
+additiveExpression
+ : multiplicativeExpression (('+' | '-') multiplicativeExpression)*
+ ;
+
+multiplicativeExpression
+ : unaryExpression (('*' | '/') unaryExpression)*
+ ;
+
+unaryExpression
+ : ('-' | '!') unaryExpression
+ | updateOperator IDENTIFIER
+ | postfixExpression
+ ;
+
+// Prefix updates require a local name; postfix updates also allow fields
+// and array elements. All updates require an assignable operand.
+updateOperator : '++' | '--' ;
+postfixExpression : primaryExpression postfixSuffix* updateOperator? ;
+postfixSuffix : '.' IDENTIFIER | '[' assignment ']' | '#' | callSuffix | methodCallSuffix ;
+
+// For a fixed function-valued member, object.name(args) passes object as self.
+// This overlaps ordinary field selection followed by a call syntactically;
+// name/type resolution determines which call form applies.
+methodCallSuffix : '.' IDENTIFIER callSuffix ;
+
+primaryExpression
+ : INTEGER_LITERAL
+ | FLOAT_LITERAL
+ | STRING_LITERAL
+ | CHARACTER_LITERAL
+ | 'true'
+ | 'false'
+ | 'null'
+ | IDENTIFIER
+ | '(' assignment ')'
+ | newExpression
+ | functionExpression
+ ;
+
+// A function is an expression bound with an ordinary declaration.
+// Its last statement supplies the implicit result; return can exit earlier.
+functionExpression : '{' parameterList? '->' statement* '}' ;
+parameterList : (parameter ','?)+ ;
+parameter : type bindingModifier? IDENTIFIER ;
+
+// Function types have unnamed, space-separated argument types.
+// {int} is the zero-argument type; its function expression still uses ->.
+functionType
+ : '{' type+ '->' type '}' '?'?
+ | '{' type '}' '?'?
+ ;
+
+callSuffix : '(' argumentList? ')' ;
+argumentList : assignment (',' assignment)* ','? ;
+
+// Struct initialization uses a block; array allocation supplies a length.
+newExpression : 'new' type ('[' assignment ']' | block)? ;
+
+INTEGER_LITERAL : '0' | [1-9] DIGIT* ;
+FLOAT_LITERAL : DIGIT+ ('.' DIGIT* ('e' DIGIT+)? | 'e' '-'? DIGIT+) ;
+STRING_LITERAL : '"' (ESCAPE | ~["\\])* '"' ;
+CHARACTER_LITERAL : '\'' (ESCAPE | ~['\\]) '\'' ;
+fragment ESCAPE : '\\' [0ntr\\'"] ;
+IDENTIFIER : NON_DIGIT (NON_DIGIT | DIGIT)* ;
+fragment NON_DIGIT : [a-zA-Z_] ;
+fragment DIGIT : [0-9] ;
+WHITESPACE : [ \t\r\n]+ -> skip ;
+LINE_COMMENT : '//' ~[\r\n]* -> skip ;
+BLOCK_COMMENT : '/*' .*? '*/' -> skip ;
+```