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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package token defines constants representing the lexical tokens of the gcfg
// configuration syntax and basic operations on tokens (printing, predicates).
//
// Note that the API for the token package may change to accommodate new
// features or implementation changes in gcfg.
//
package token
import "strconv"
// Token is the set of lexical tokens of the gcfg configuration syntax.
type Token int
// The list of tokens.
const (
// Special tokens
ILLEGAL Token = iota
EOF
COMMENT
literal_beg
// Identifiers and basic type literals
// (these tokens stand for classes of literals)
IDENT // section-name, variable-name
STRING // "subsection-name", variable value
literal_end
operator_beg
// Operators and delimiters
ASSIGN // =
LBRACK // [
RBRACK // ]
EOL // \n
operator_end
)
var tokens = [...]string{
ILLEGAL: "ILLEGAL",
EOF: "EOF",
COMMENT: "COMMENT",
IDENT: "IDENT",
STRING: "STRING",
ASSIGN: "=",
LBRACK: "[",
RBRACK: "]",
EOL: "\n",
}
// String returns the string corresponding to the token tok.
// For operators and delimiters, the string is the actual token character
// sequence (e.g., for the token ASSIGN, 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").
//
func (tok Token) String() string {
s := ""
if 0 <= tok && tok < Token(len(tokens)) {
s = tokens[tok]
}
if s == "" {
s = "token(" + strconv.Itoa(int(tok)) + ")"
}
return s
}
// Predicates
// IsLiteral returns true for tokens corresponding to identifiers
// and basic type literals; it returns false otherwise.
//
func (tok Token) IsLiteral() bool { return literal_beg < tok && tok < literal_end }
// IsOperator returns true for tokens corresponding to operators and
// delimiters; it returns false otherwise.
//
func (tok Token) IsOperator() bool { return operator_beg < tok && tok < operator_end }
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