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add switch statement to language reference

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Andrew Kelley 2016-01-19 19:15:36 -07:00
parent 890714b8ca
commit 17e574fec6
1 changed files with 60 additions and 54 deletions
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doc/langref.md
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@ -30,139 +30,145 @@ zig | C equivalent | Description
## Grammar ## Grammar
``` ```
Root : many(TopLevelDecl) token(EOF) Root : many(TopLevelDecl) "EOF"
TopLevelDecl : FnDef | ExternBlock | RootExportDecl | Import | ContainerDecl | VariableDeclaration TopLevelDecl : FnDef | ExternBlock | RootExportDecl | Import | ContainerDecl | VariableDeclaration
VariableDeclaration : option(FnVisibleMod) (token(Var) | token(Const)) token(Symbol) (token(Eq) Expression | token(Colon) PrefixOpExpression option(token(Eq) Expression)) VariableDeclaration : option(FnVisibleMod) ("var" | "const") "symbol" ("=" Expression | ":" PrefixOpExpression option("=" Expression))
ContainerDecl : many(Directive) option(FnVisibleMod) (token(Struct) | token(Enum)) token(Symbol) token(LBrace) many(StructMember) token(RBrace) ContainerDecl : many(Directive) option(FnVisibleMod) ("struct" | "enum") "Symbol" "{" many(StructMember) "}"
StructMember: StructField | FnDecl StructMember: StructField | FnDecl
StructField : token(Symbol) option(token(Colon) Expression) token(Comma)) StructField : "Symbol" option(":" Expression) ",")
Import : many(Directive) token(Import) token(String) token(Semicolon) Import : many(Directive) "import" "String" ";"
RootExportDecl : many(Directive) token(Export) token(Symbol) token(String) token(Semicolon) RootExportDecl : many(Directive) "export" "Symbol" "String" ";"
ExternBlock : many(Directive) token(Extern) token(LBrace) many(FnDecl) token(RBrace) ExternBlock : many(Directive) "extern" "{" many(FnDecl) "}"
FnProto : many(Directive) option(FnVisibleMod) token(Fn) token(Symbol) ParamDeclList option(PrefixOpExpression) FnProto : many(Directive) option(FnVisibleMod) "fn" "Symbol" ParamDeclList option(PrefixOpExpression)
Directive : token(NumberSign) token(Symbol) token(LParen) token(String) token(RParen) Directive : "#" "Symbol" "(" "String" ")"
FnVisibleMod : token(Pub) | token(Export) FnVisibleMod : "pub" | "export"
FnDecl : FnProto token(Semicolon) FnDecl : FnProto ";"
FnDef : FnProto token(FatArrow) Block FnDef : FnProto "=>" Block
ParamDeclList : token(LParen) list(ParamDecl, token(Comma)) token(RParen) ParamDeclList : "(" list(ParamDecl, ",") ")"
ParamDecl : option(token(NoAlias)) token(Symbol) token(Colon) PrefixOpExpression | token(Ellipsis) ParamDecl : option("noalias") "Symbol" ":" PrefixOpExpression | "..."
Block : token(LBrace) list(option(Statement), token(Semicolon)) token(RBrace) Block : "{" list(option(Statement), ";") "}"
Statement : Label | VariableDeclaration token(Semicolon) | NonBlockExpression token(Semicolon) | BlockExpression Statement : Label | VariableDeclaration ";" | NonBlockExpression ";" | BlockExpression
Label: token(Symbol) token(Colon) Label: "Symbol" ":"
Expression : BlockExpression | NonBlockExpression Expression : BlockExpression | NonBlockExpression
NonBlockExpression : ReturnExpression | AssignmentExpression NonBlockExpression : ReturnExpression | AssignmentExpression
AsmExpression : token(Asm) option(token(Volatile)) token(LParen) token(String) option(AsmOutput) token(RParen) AsmExpression : "asm" option("volatile") "(" "String" option(AsmOutput) ")"
AsmOutput : token(Colon) list(AsmOutputItem, token(Comma)) option(AsmInput) AsmOutput : ":" list(AsmOutputItem, ",") option(AsmInput)
AsmInput : token(Colon) list(AsmInputItem, token(Comma)) option(AsmClobbers) AsmInput : ":" list(AsmInputItem, ",") option(AsmClobbers)
AsmOutputItem : token(LBracket) token(Symbol) token(RBracket) token(String) token(LParen) (token(Symbol) | token(Arrow) PrefixOpExpression) token(RParen) AsmOutputItem : "[" "Symbol" "]" "String" "(" ("Symbol" | "->" PrefixOpExpression) ")"
AsmInputItem : token(LBracket) token(Symbol) token(RBracket) token(String) token(LParen) Expression token(RParen) AsmInputItem : "[" "Symbol" "]" "String" "(" Expression ")"
AsmClobbers: token(Colon) list(token(String), token(Comma)) AsmClobbers: ":" list("String", ",")
UnwrapMaybeExpression : BoolOrExpression token(DoubleQuestionMark) BoolOrExpression | BoolOrExpression UnwrapMaybeExpression : BoolOrExpression "??" BoolOrExpression | BoolOrExpression
AssignmentExpression : UnwrapMaybeExpression AssignmentOperator UnwrapMaybeExpression | UnwrapMaybeExpression AssignmentExpression : UnwrapMaybeExpression AssignmentOperator UnwrapMaybeExpression | UnwrapMaybeExpression
AssignmentOperator : token(Eq) | token(TimesEq) | token(DivEq) | token(ModEq) | token(PlusEq) | token(MinusEq) | token(BitShiftLeftEq) | token(BitShiftRightEq) | token(BitAndEq) | token(BitXorEq) | token(BitOrEq) | token(BoolAndEq) | token(BoolOrEq) AssignmentOperator : "=" | "*=" | "/=" | "%=" | "+=" | "-=" | "<<=" | ">>=" | "&=" | "^=" | "|=" | "&&=" | "||="
BlockExpression : IfExpression | Block | WhileExpression | ForExpression BlockExpression : IfExpression | Block | WhileExpression | ForExpression | SwitchExpression
WhileExpression : token(While) token(LParen) Expression token(RParen) Expression SwitchExpression : "switch" "(" Expression ")" "{" many(SwitchProng) "}"
ForExpression : token(For) token(LParen) Symbol token(Comma) Expression option(token(Comma) token(Symbol)) token(RParen) Expression SwitchProng : (list(SwitchItem, ",") | "else") option("(" "Symbol" ")") "=>" Expression ","
BoolOrExpression : BoolAndExpression token(BoolOr) BoolOrExpression | BoolAndExpression SwitchItem : Expression | (Expression "..." Expression)
ReturnExpression : token(Return) option(Expression) WhileExpression : "while" "(" Expression ")" Expression
ForExpression : "for" "(" "Symbol" "," Expression option("," "Symbol") ")" Expression
BoolOrExpression : BoolAndExpression "||" BoolOrExpression | BoolAndExpression
ReturnExpression : "return" option(Expression)
IfExpression : IfVarExpression | IfBoolExpression IfExpression : IfVarExpression | IfBoolExpression
IfBoolExpression : token(If) token(LParen) Expression token(RParen) Expression option(Else) IfBoolExpression : "if" "(" Expression ")" Expression option(Else)
IfVarExpression : token(If) token(LParen) (token(Const) | token(Var)) token(Symbol) option(token(Colon) PrefixOpExpression) Token(MaybeAssign) Expression token(RParen) Expression Option(Else) IfVarExpression : "if" "(" ("const" | "var") "Symbol" option(":" PrefixOpExpression) "?=" Expression ")" Expression Option(Else)
Else : token(Else) Expression Else : "else" Expression
BoolAndExpression : ComparisonExpression token(BoolAnd) BoolAndExpression | ComparisonExpression BoolAndExpression : ComparisonExpression "&&" BoolAndExpression | ComparisonExpression
ComparisonExpression : BinaryOrExpression ComparisonOperator BinaryOrExpression | BinaryOrExpression ComparisonExpression : BinaryOrExpression ComparisonOperator BinaryOrExpression | BinaryOrExpression
ComparisonOperator : token(BoolEq) | token(BoolNotEq) | token(BoolLessThan) | token(BoolGreaterThan) | token(BoolLessEqual) | token(BoolGreaterEqual) ComparisonOperator : "==" | "!=" | "<" | ">" | "<=" | ">="
BinaryOrExpression : BinaryXorExpression token(BinOr) BinaryOrExpression | BinaryXorExpression BinaryOrExpression : BinaryXorExpression "|" BinaryOrExpression | BinaryXorExpression
BinaryXorExpression : BinaryAndExpression token(BinXor) BinaryXorExpression | BinaryAndExpression BinaryXorExpression : BinaryAndExpression "^" BinaryXorExpression | BinaryAndExpression
BinaryAndExpression : BitShiftExpression token(Ampersand) BinaryAndExpression | BitShiftExpression BinaryAndExpression : BitShiftExpression "&" BinaryAndExpression | BitShiftExpression
BitShiftExpression : AdditionExpression BitShiftOperator BitShiftExpression | AdditionExpression BitShiftExpression : AdditionExpression BitShiftOperator BitShiftExpression | AdditionExpression
BitShiftOperator : token(BitShiftLeft) | token(BitShiftRight) BitShiftOperator : "<<" | ">>"
AdditionExpression : MultiplyExpression AdditionOperator AdditionExpression | MultiplyExpression AdditionExpression : MultiplyExpression AdditionOperator AdditionExpression | MultiplyExpression
AdditionOperator : token(Plus) | token(Minus) AdditionOperator : "+" | "-"
MultiplyExpression : CurlySuffixExpression MultiplyOperator MultiplyExpression | CurlySuffixExpression MultiplyExpression : CurlySuffixExpression MultiplyOperator MultiplyExpression | CurlySuffixExpression
CurlySuffixExpression : PrefixOpExpression option(ContainerInitExpression) CurlySuffixExpression : PrefixOpExpression option(ContainerInitExpression)
MultiplyOperator : token(Star) | token(Slash) | token(Percent) MultiplyOperator : "*" | "/" | "%"
PrefixOpExpression : PrefixOp PrefixOpExpression | SuffixOpExpression PrefixOpExpression : PrefixOp PrefixOpExpression | SuffixOpExpression
SuffixOpExpression : PrimaryExpression option(FnCallExpression | ArrayAccessExpression | FieldAccessExpression | SliceExpression) SuffixOpExpression : PrimaryExpression option(FnCallExpression | ArrayAccessExpression | FieldAccessExpression | SliceExpression)
FieldAccessExpression : token(Dot) token(Symbol) FieldAccessExpression : "." "Symbol"
FnCallExpression : token(LParen) list(Expression, token(Comma)) token(RParen) FnCallExpression : "(" list(Expression, ",") ")"
ArrayAccessExpression : token(LBracket) Expression token(RBracket) ArrayAccessExpression : "[" Expression "]"
SliceExpression : token(LBracket) Expression token(Ellipsis) option(Expression) token(RBracket) option(token(Const)) SliceExpression : "[" Expression "..." option(Expression) "]" option("const")
ContainerInitExpression : token(LBrace) ContainerInitBody token(RBrace) ContainerInitExpression : "{" ContainerInitBody "}"
ContainerInitBody : list(StructLiteralField, token(Comma)) | list(Expression, token(Comma)) ContainerInitBody : list(StructLiteralField, ",") | list(Expression, ",")
StructLiteralField : token(Dot) token(Symbol) token(Eq) Expression StructLiteralField : "." "Symbol" "=" Expression
PrefixOp : token(Not) | token(Dash) | token(Tilde) | token(Star) | (token(Ampersand) option(token(Const))) | token(QuestionMark) PrefixOp : "!" | "-" | "~" | "*" | ("&" option("const")) | "?"
PrimaryExpression : token(Number) | token(String) | token(CharLiteral) | KeywordLiteral | GroupedExpression | GotoExpression | BlockExpression | token(Symbol) | (token(AtSign) token(Symbol) FnCallExpression) | ArrayType | AsmExpression PrimaryExpression : "Number" | "String" | "CharLiteral" | KeywordLiteral | GroupedExpression | GotoExpression | BlockExpression | "Symbol" | ("@" "Symbol" FnCallExpression) | ArrayType | AsmExpression
ArrayType : token(LBracket) option(Expression) token(RBracket) option(token(Const)) PrefixOpExpression ArrayType : "[" option(Expression) "]" option("const") PrefixOpExpression
GotoExpression: token(Goto) token(Symbol) GotoExpression: "goto" "Symbol"
GroupedExpression : token(LParen) Expression token(RParen) GroupedExpression : "(" Expression ")"
KeywordLiteral : token(True) | token(False) | token(Null) | token(Break) | token(Continue) KeywordLiteral : "true" | "false" | "null" | "break" | "continue"
``` ```
## Operator Precedence ## Operator Precedence