Documentation
¶
Overview ¶
Package token defines constants representing the lexical tokens of the Go+ programming language and basic operations on tokens (printing, predicates).
Index ¶
Constants ¶
const ( LowestPrec = 0 // non-operators UnaryPrec = 6 HighestPrec = 7 )
A set of constants for precedence-based expression parsing. Non-operators have lowest precedence, followed by operators starting with precedence 1 up to unary operators. The highest precedence serves as "catch-all" precedence for selector, indexing, and other operator and delimiter tokens.
const ( // NoPos - The zero value for Pos is NoPos; there is no file and line // information associated with it, and NoPos.IsValid() is false. NoPos // is always smaller than any other Pos value. The corresponding // Position value for NoPos is the zero value for Position. NoPos = token.NoPos )
Variables ¶
This section is empty.
Functions ¶
func IsExported ¶
IsExported reports whether name starts with an upper-case letter.
func IsIdentifier ¶
IsIdentifier reports whether name is a Go identifier, that is, a non-empty string made up of letters, digits, and underscores, where the first character is not a digit. Keywords are not identifiers.
Types ¶
type File ¶
A File is a handle for a file belonging to a FileSet. A File has a name, size, and line offset table.
type FileSet ¶
A FileSet represents a set of source files. Methods of file sets are synchronized; multiple goroutines may invoke them concurrently.
type Pos ¶
Pos is a compact encoding of a source position within a file set. It can be converted into a Position for a more convenient, but much larger, representation.
The Pos value for a given file is a number in the range [base, base+size], where base and size are specified when adding the file to the file set via AddFile.
To create the Pos value for a specific source offset (measured in bytes), first add the respective file to the current file set using FileSet.AddFile and then call File.Pos(offset) for that file. Given a Pos value p for a specific file set fset, the corresponding Position value is obtained by calling fset.Position(p).
Pos values can be compared directly with the usual comparison operators: If two Pos values p and q are in the same file, comparing p and q is equivalent to comparing the respective source file offsets. If p and q are in different files, p < q is true if the file implied by p was added to the respective file set before the file implied by q.
type Position ¶
Position describes an arbitrary source position including the file, line, and column location. A Position is valid if the line number is > 0.
type Token ¶
type Token int
Token is the set of lexical tokens of the Go programming language.
const ( // Special tokens ILLEGAL Token = iota EOF COMMENT // Identifiers and basic type literals // (these tokens stand for classes of literals) IDENT // main INT // 12345 FLOAT // 123.45 IMAG // 123.45i CHAR // 'a' STRING // "abc" // Operators and delimiters ADD // + SUB // - MUL // * QUO // / REM // % AND // & OR // | XOR // ^ SHL // << SHR // >> AND_NOT // &^ ADD_ASSIGN // += SUB_ASSIGN // -= MUL_ASSIGN // *= QUO_ASSIGN // /= REM_ASSIGN // %= AND_ASSIGN // &= OR_ASSIGN // |= XOR_ASSIGN // ^= SHL_ASSIGN // <<= SHR_ASSIGN // >>= AND_NOT_ASSIGN // &^= LAND // && LOR // || ARROW // <- INC // ++ DEC // -- EQL // == LSS // < GTR // > ASSIGN // = NOT // ! NEQ // != LEQ // <= GEQ // >= DEFINE // := ELLIPSIS // ... LPAREN // ( LBRACK // [ LBRACE // { COMMA // , PERIOD // . RPAREN // ) RBRACK // ] RBRACE // } SEMICOLON // ; COLON // : // Keywords BREAK CASE CHAN CONST CONTINUE DEFAULT DEFER ELSE FALLTHROUGH FOR FUNC GO GOTO IF IMPORT INTERFACE MAP PACKAGE RANGE RETURN SELECT STRUCT SWITCH TYPE VAR RAT = literal_end // 123.5r QUESTION = operator_end // ? )
The list of tokens.
func (Token) IsKeyword ¶
IsKeyword returns true for tokens corresponding to keywords; it returns false otherwise.
func (Token) IsLiteral ¶
IsLiteral returns true for tokens corresponding to identifiers and basic type literals; it returns false otherwise.
func (Token) IsOperator ¶
IsOperator returns true for tokens corresponding to operators and delimiters; it returns false otherwise.
func (Token) Precedence ¶
Precedence returns the operator precedence of the binary operator op. If op is not a binary operator, the result is LowestPrecedence.
func (Token) String ¶
String returns the string corresponding to the token tok. For operators, delimiters, and keywords the string is the actual token character sequence (e.g., for the token ADD, the string is "+"). For all other tokens the string corresponds to the token constant name (e.g. for the token IDENT, the string is "IDENT").
Source Files