mirror of
https://github.com/jashkenas/coffeescript.git
synced 2026-02-18 19:34:27 -05:00
completely reorganized for a gem and the 'coffee-script' command
This commit is contained in:
Jeremy Ashkenas
294
lib/coffee_script/grammar.y
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294
lib/coffee_script/grammar.y
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class Parser
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# Declare tokens produced by the lexer
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token IF ELSE THEN UNLESS
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token NUMBER STRING REGEX
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token TRUE FALSE NULL
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token IDENTIFIER PROPERTY_ACCESS
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token CODE PARAM NEW RETURN
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token TRY CATCH FINALLY THROW
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token BREAK CONTINUE
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token FOR IN WHILE
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token SWITCH CASE DEFAULT
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token NEWLINE
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token JS
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# Declare order of operations.
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prechigh
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nonassoc UMINUS NOT '!'
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left '*' '/' '%'
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left '+' '-'
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left '<=' '<' '>' '>='
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right '==' '!=' IS AINT
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left '&&' '||' AND OR
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left ':'
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right '-=' '+=' '/=' '*=' '||=' '&&='
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nonassoc IF
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left UNLESS
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right RETURN THROW FOR WHILE
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nonassoc "."
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preclow
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# We expect 2 shift/reduce errors for optional syntax.
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# There used to be 252 -- greatly improved.
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expect 2
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rule
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# All parsing will end in this rule, being the trunk of the AST.
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Root:
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/* nothing */ { result = Nodes.new([]) }
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| Terminator { result = Nodes.new([]) }
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| Expressions { result = val[0] }
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;
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# Any list of expressions or method body, seperated by line breaks or semis.
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Expressions:
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Expression { result = Nodes.new(val) }
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| Expressions Terminator Expression { result = val[0] << val[2] }
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| Expressions Terminator { result = val[0] }
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| Terminator Expressions { result = val[1] }
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;
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# All types of expressions in our language
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Expression:
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Literal
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| Value
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| Call
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| Assign
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| Code
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| Operation
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| If
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| Try
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| Throw
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| Return
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| While
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| For
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| Switch
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;
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# All tokens that can terminate an expression
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Terminator:
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"\n"
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| ";"
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;
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# All tokens that can serve to begin the second block
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Then:
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THEN
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| Terminator
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;
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# All hard-coded values
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Literal:
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NUMBER { result = LiteralNode.new(val[0]) }
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| STRING { result = LiteralNode.new(val[0]) }
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| JS { result = LiteralNode.new(val[0]) }
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| REGEX { result = LiteralNode.new(val[0]) }
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| TRUE { result = LiteralNode.new(true) }
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| FALSE { result = LiteralNode.new(false) }
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| NULL { result = LiteralNode.new(nil) }
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| BREAK { result = LiteralNode.new(val[0]) }
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| CONTINUE { result = LiteralNode.new(val[0]) }
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;
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# Assign to a variable
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Assign:
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Value ":" Expression { result = AssignNode.new(val[0], val[2]) }
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;
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# Assignment within an object literal.
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AssignObj:
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IDENTIFIER ":" Expression { result = AssignNode.new(val[0], val[2], :object) }
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;
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# A Return statement.
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Return:
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RETURN Expression { result = ReturnNode.new(val[1]) }
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;
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# Arithmetic and logical operators
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# For Ruby's Operator precedence, see:
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# https://www.cs.auckland.ac.nz/references/ruby/ProgrammingRuby/language.html
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Operation:
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'!' Expression { result = OpNode.new(val[0], val[1]) }
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| '-' Expression = UMINUS { result = OpNode.new(val[0], val[1]) }
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| NOT Expression { result = OpNode.new(val[0], val[1]) }
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| Expression '*' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '/' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '%' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '+' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '-' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '<=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '<' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '>' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '>=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '==' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '!=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression IS Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression AINT Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '&&' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '||' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression AND Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression OR Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '-=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '+=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '/=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '*=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '||=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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| Expression '&&=' Expression { result = OpNode.new(val[1], val[0], val[2]) }
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;
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# Method definition
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Code:
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ParamList "=>" Expressions "." { result = CodeNode.new(val[0], val[2]) }
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| "=>" Expressions "." { result = CodeNode.new([], val[1]) }
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;
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ParamList:
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PARAM { result = val }
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| ParamList "," PARAM { result = val[0] << val[2] }
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;
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Value:
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IDENTIFIER { result = ValueNode.new(val) }
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| Array { result = ValueNode.new(val) }
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| Object { result = ValueNode.new(val) }
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| Parenthetical { result = ValueNode.new(val) }
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| Value Accessor { result = val[0] << val[1] }
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| Invocation Accessor { result = ValueNode.new(val[0], [val[1]]) }
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;
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Accessor:
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PROPERTY_ACCESS IDENTIFIER { result = AccessorNode.new(val[1]) }
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| Index { result = val[0] }
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| Slice { result = val[0] }
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;
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Index:
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"[" Expression "]" { result = IndexNode.new(val[1]) }
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;
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Slice:
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"[" Expression "," Expression "]" { result = SliceNode.new(val[1], val[3]) }
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;
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Object:
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"{" AssignList "}" { result = ObjectNode.new(val[1]) }
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;
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AssignList:
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/* nothing */ { result = []}
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| AssignObj { result = val }
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| AssignList "," AssignObj { result = val[0] << val[2] }
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| AssignList Terminator AssignObj { result = val[0] << val[2] }
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;
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# A method call.
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Call:
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Invocation { result = val[0] }
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| NEW Invocation { result = val[1].new_instance }
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;
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Invocation:
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Value "(" ArgList ")" { result = CallNode.new(val[0], val[2]) }
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;
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# An Array.
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Array:
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"[" ArgList "]" { result = ArrayNode.new(val[1]) }
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;
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# A list of arguments to a method call.
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ArgList:
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/* nothing */ { result = [] }
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| Expression { result = val }
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| ArgList "," Expression { result = val[0] << val[2] }
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| ArgList Terminator Expression { result = val[0] << val[2] }
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;
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If:
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IF Expression
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Then Expressions "." { result = IfNode.new(val[1], val[3]) }
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| IF Expression
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Then Expressions
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ELSE Expressions "." { result = IfNode.new(val[1], val[3], val[5]) }
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| Expression IF Expression { result = IfNode.new(val[2], Nodes.new([val[0]])) }
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| Expression UNLESS Expression { result = IfNode.new(val[2], Nodes.new([val[0]]), nil, :invert) }
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;
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Try:
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TRY Expressions CATCH IDENTIFIER
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Expressions "." { result = TryNode.new(val[1], val[3], val[4]) }
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| TRY Expressions FINALLY
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Expressions "." { result = TryNode.new(val[1], nil, nil, val[3]) }
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| TRY Expressions CATCH IDENTIFIER
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Expressions
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FINALLY Expressions "." { result = TryNode.new(val[1], val[3], val[4], val[6]) }
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;
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Throw:
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THROW Expression { result = ThrowNode.new(val[1]) }
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;
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Parenthetical:
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"(" Expressions ")" { result = ParentheticalNode.new(val[1]) }
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;
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While:
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WHILE Expression Then
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Expressions "." { result = WhileNode.new(val[1], val[3]) }
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;
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For:
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Expression FOR IDENTIFIER
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IN Expression "." { result = ForNode.new(val[0], val[4], val[2]) }
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| Expression FOR
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IDENTIFIER "," IDENTIFIER
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IN Expression "." { result = ForNode.new(val[0], val[6], val[2], val[4]) }
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| Expression FOR IDENTIFIER
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IN Expression
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IF Expression "." { result = ForNode.new(IfNode.new(val[6], Nodes.new([val[0]])), val[4], val[2]) }
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| Expression FOR
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IDENTIFIER "," IDENTIFIER
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IN Expression
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IF Expression "." { result = ForNode.new(IfNode.new(val[8], Nodes.new([val[0]])), val[6], val[2], val[4]) }
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;
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Switch:
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SWITCH Expression Then
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Cases "." { result = val[3].rewrite_condition(val[1]) }
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| SWITCH Expression Then
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Cases DEFAULT Expressions "." { result = val[3].rewrite_condition(val[1]).add_default(val[5]) }
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;
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Cases:
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Case { result = val[0] }
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| Cases Case { result = val[0] << val[1] }
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;
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Case:
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CASE Expression Then Expressions { result = IfNode.new(val[1], val[3]) }
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;
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end
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---- inner
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def parse(code, show_tokens=false)
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# @yydebug = true
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@tokens = Lexer.new.tokenize(code)
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puts @tokens.inspect if show_tokens
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do_parse
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end
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def next_token
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@tokens.shift
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end
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