1065 lines
20 KiB
Go
1065 lines
20 KiB
Go
// Copyright © 2016 Abcum Ltd
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package sql
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import (
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"bufio"
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"bytes"
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"io"
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"regexp"
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"strconv"
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"strings"
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"time"
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)
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// scanner represents a lexical scanner.
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type scanner struct {
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b []rune // any runes before
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a []rune // any runes after
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r *bufio.Reader
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}
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// newScanner returns a new instance of Scanner.
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func newScanner(r io.Reader) *scanner {
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return &scanner{r: bufio.NewReader(r)}
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}
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// scan returns the next token and literal value.
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func (s *scanner) scan() (tok Token, lit string, val interface{}) {
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// Read the next rune.
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ch := s.next()
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// If we see whitespace then consume all contiguous whitespace.
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if isBlank(ch) {
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return s.scanBlank(ch)
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}
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// If we see a letter then consume as a string.
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if isLetter(ch) {
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return s.scanIdiom(ch)
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}
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// If we see a number then consume as a number.
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if isNumber(ch) {
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return s.scanNumber(ch)
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}
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// Otherwise read the individual character.
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switch ch {
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case eof:
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return EOF, "", val
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case '*':
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return MUL, string(ch), val
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case '×':
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return MUL, string(ch), val
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case '∙':
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return MUL, string(ch), val
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case '÷':
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return DIV, string(ch), val
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case ',':
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return COMMA, string(ch), val
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case '.':
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return DOT, string(ch), val
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case '@':
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return s.scanThing(ch)
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case '"':
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return s.scanString(ch)
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case '\'':
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return s.scanString(ch)
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case '`':
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return s.scanQuoted(ch)
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case '⟨':
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return s.scanQuoted(ch)
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case '{':
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return s.scanObject(ch)
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case '[':
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return s.scanObject(ch)
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case '$':
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return s.scanParams(ch)
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case ':':
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return COLON, string(ch), val
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case ';':
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return SEMICOLON, string(ch), val
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case '(':
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return LPAREN, string(ch), val
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case ')':
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return RPAREN, string(ch), val
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case '¬':
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return NEQ, string(ch), val
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case '≤':
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return LTE, string(ch), val
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case '≥':
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return GTE, string(ch), val
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case '~':
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return MAT, string(ch), val
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case '∋':
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return SIN, string(ch), val
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case '∌':
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return SNI, string(ch), val
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case '⊇':
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return CONTAINSALL, string(ch), val
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case '⊃':
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return CONTAINSSOME, string(ch), val
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case '⊅':
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return CONTAINSNONE, string(ch), val
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case '∈':
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return INS, string(ch), val
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case '∉':
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return NIS, string(ch), val
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case '⊆':
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return ALLCONTAINEDIN, string(ch), val
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case '⊂':
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return SOMECONTAINEDIN, string(ch), val
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case '⊄':
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return NONECONTAINEDIN, string(ch), val
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case '#':
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return s.scanCommentSingle(ch)
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case '|':
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chn := s.next()
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switch {
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case chn == '|':
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return OR, "OR", val
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default:
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s.undo()
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return s.scanModel(ch)
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}
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case '&':
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chn := s.next()
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switch {
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case chn == '&':
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return AND, "AND", val
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default:
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s.undo()
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}
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case '/':
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chn := s.next()
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switch {
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case chn == '/':
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return s.scanCommentSingle(ch)
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case chn == '*':
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return s.scanCommentMultiple(ch)
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case isNumber(chn):
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s.undo()
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return DIV, string(ch), val
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||
case chn == ' ':
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s.undo()
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return DIV, string(ch), val
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default:
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s.undo()
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return s.scanRegexp(ch)
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||
}
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case '=':
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chn := s.next()
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switch {
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case chn == '~':
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return MAT, "=~", val
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||
case chn == '=':
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return EEQ, "==", val
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default:
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s.undo()
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return EQ, string(ch), val
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||
}
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case '?':
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chn := s.next()
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switch {
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case chn == '=':
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return ANY, "?=", val
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case chn == '~':
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return MAY, "?~", val
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||
default:
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s.undo()
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return QMARK, string(ch), val
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}
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case '!':
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chn := s.next()
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switch {
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case chn == '=':
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if s.next() == '=' {
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return NEE, "!==", val
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} else {
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s.undo()
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return NEQ, "!=", val
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}
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case chn == '~':
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return NAT, "!~", val
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default:
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s.undo()
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return EXC, string(ch), val
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}
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case '+':
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chn := s.next()
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switch {
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case chn == '=':
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return INC, "+=", val
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case isNumber(chn):
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return s.scanNumber(ch, chn)
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default:
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s.undo()
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return ADD, string(ch), val
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}
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case '-':
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chn := s.next()
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switch {
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case chn == '=':
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return DEC, "-=", val
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case chn == '>':
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return OEDGE, "->", val
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case chn == '-':
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return s.scanCommentSingle(ch)
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||
case isNumber(chn):
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return s.scanNumber(ch, chn)
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default:
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s.undo()
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return SUB, string(ch), val
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}
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case '>':
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chn := s.next()
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switch {
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case chn == '=':
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return GTE, ">=", val
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default:
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s.undo()
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return GT, string(ch), val
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}
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case '<':
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chn := s.next()
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switch {
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case chn == '>':
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return NEQ, "<>", val
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case chn == '=':
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return LTE, "<=", val
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case chn == '-':
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if s.next() == '>' {
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return BEDGE, "<->", val
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} else {
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s.undo()
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return IEDGE, "<-", val
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}
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default:
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s.undo()
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return LT, string(ch), val
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}
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}
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return ILLEGAL, string(ch), val
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}
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// scanBlank consumes the current rune and all contiguous whitespace.
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func (s *scanner) scanBlank(chp ...rune) (tok Token, lit string, val interface{}) {
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tok = WS
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// Create a buffer
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var buf bytes.Buffer
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// Read passed in runes
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for _, ch := range chp {
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buf.WriteRune(ch)
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}
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// Read subsequent characters
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for {
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if ch := s.next(); ch == eof {
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break
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} else if !isBlank(ch) {
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s.undo()
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break
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} else {
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buf.WriteRune(ch)
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}
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}
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return tok, buf.String(), val
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}
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// scanCommentSingle consumes the current rune and all contiguous whitespace.
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func (s *scanner) scanCommentSingle(chp ...rune) (tok Token, lit string, val interface{}) {
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tok = WS
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// Create a buffer
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var buf bytes.Buffer
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// Read passed in runes
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for _, ch := range chp {
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buf.WriteRune(ch)
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}
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// Read subsequent characters
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for {
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if ch := s.next(); ch == eof {
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break
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} else if ch == '\n' || ch == '\r' {
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buf.WriteRune(ch)
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break
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} else {
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buf.WriteRune(ch)
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}
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}
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return tok, buf.String(), val
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}
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// scanCommentMultiple consumes the current rune and all contiguous whitespace.
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func (s *scanner) scanCommentMultiple(chp ...rune) (tok Token, lit string, val interface{}) {
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||
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tok = WS
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||
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// Create a buffer
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||
var buf bytes.Buffer
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||
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||
// Read passed in runes
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for _, ch := range chp {
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buf.WriteRune(ch)
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}
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// Read subsequent characters
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for {
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if ch := s.next(); ch == eof {
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break
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} else if ch == '*' {
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if chn := s.next(); chn == '/' {
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buf.WriteRune(chn)
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break
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}
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buf.WriteRune(ch)
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} else {
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||
buf.WriteRune(ch)
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||
}
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||
}
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return tok, buf.String(), val
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}
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func (s *scanner) scanParams(chp ...rune) (tok Token, lit string, val interface{}) {
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tok, lit, _ = s.scanIdiom()
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if is(tok, THING) {
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return ILLEGAL, lit, val
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}
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if is(tok, REGION) {
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return ILLEGAL, lit, val
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}
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if is(tok, ILLEGAL) {
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||
return ILLEGAL, lit, val
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||
}
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||
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return PARAM, lit, val
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}
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func (s *scanner) scanQuoted(chp ...rune) (tok Token, lit string, val interface{}) {
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||
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||
var tbv string
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var idv interface{}
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||
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// Create a buffer
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||
var buf bytes.Buffer
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||
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tok, lit, _ = s.scanString(chp...)
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||
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||
if is(tok, REGION) {
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return ILLEGAL, lit, val
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||
}
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||
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||
if is(tok, ILLEGAL) {
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||
return ILLEGAL, lit, val
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||
}
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||
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if ch := s.next(); ch == ':' {
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||
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tbv = lit
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buf.WriteString(lit)
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||
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||
buf.WriteRune(ch)
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||
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||
if tok, lit, idv = s.part(); tok == ILLEGAL {
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buf.WriteString(lit)
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||
return ILLEGAL, buf.String(), val
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||
} else {
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||
buf.WriteString(lit)
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||
}
|
||
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||
return THING, buf.String(), NewThing(tbv, idv)
|
||
|
||
} else if ch != eof {
|
||
s.undo()
|
||
}
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||
|
||
return IDENT, lit, val
|
||
|
||
}
|
||
|
||
func (s *scanner) scanSection(chp ...rune) (tok Token, lit string, val interface{}) {
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||
|
||
tok, lit, _ = s.scanString(chp...)
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||
|
||
if is(tok, REGION) {
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||
return ILLEGAL, lit, val
|
||
}
|
||
|
||
if is(tok, ILLEGAL) {
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||
return ILLEGAL, lit, val
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||
}
|
||
|
||
return IDENT, lit, val
|
||
|
||
}
|
||
|
||
// scanIdent consumes the current rune and all contiguous ident runes.
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||
func (s *scanner) scanIdent(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
tok = IDENT
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Read passed in runes
|
||
for _, ch := range chp {
|
||
buf.WriteRune(ch)
|
||
}
|
||
|
||
// Read subsequent characters
|
||
for {
|
||
if ch := s.next(); ch == eof {
|
||
break
|
||
} else if isIdentChar(ch) {
|
||
buf.WriteRune(ch)
|
||
} else {
|
||
s.undo()
|
||
break
|
||
}
|
||
}
|
||
|
||
// If the string matches a keyword then return that keyword.
|
||
if tok := keywords[strings.ToUpper(buf.String())]; tok > 0 {
|
||
return tok, buf.String(), val
|
||
}
|
||
|
||
if val, err := time.ParseDuration(buf.String()); err == nil {
|
||
return DURATION, buf.String(), val
|
||
}
|
||
|
||
// Otherwise return as a regular identifier.
|
||
return tok, buf.String(), val
|
||
|
||
}
|
||
|
||
// scanIdiom consumes the current rune and all contiguous ident runes.
|
||
func (s *scanner) scanIdiom(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
tok = IDENT
|
||
|
||
var tbv string
|
||
var idv interface{}
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Read passed in runes
|
||
for _, ch := range chp {
|
||
buf.WriteRune(ch)
|
||
}
|
||
|
||
// Read subsequent characters
|
||
for {
|
||
if ch := s.next(); ch == eof {
|
||
break
|
||
} else if isIdentChar(ch) {
|
||
buf.WriteRune(ch)
|
||
} else if isArrayChar(ch) {
|
||
tok = EXPR
|
||
buf.WriteRune(ch)
|
||
} else if isExprsChar(ch) {
|
||
tok = EXPR
|
||
buf.WriteRune(ch)
|
||
} else if ch == ':' {
|
||
|
||
if tok == EXPR {
|
||
buf.WriteRune(ch)
|
||
continue
|
||
}
|
||
|
||
tbv = buf.String()
|
||
|
||
buf.WriteRune(ch)
|
||
|
||
if tok, lit, idv = s.part(); tok == ILLEGAL {
|
||
buf.WriteString(lit)
|
||
return ILLEGAL, buf.String(), val
|
||
} else {
|
||
buf.WriteString(lit)
|
||
}
|
||
|
||
return THING, buf.String(), NewThing(tbv, idv)
|
||
|
||
} else {
|
||
s.undo()
|
||
break
|
||
}
|
||
}
|
||
|
||
// If the string matches a keyword then return that keyword.
|
||
if tok := keywords[strings.ToUpper(buf.String())]; tok > 0 {
|
||
return tok, buf.String(), val
|
||
}
|
||
|
||
if val, err := time.ParseDuration(buf.String()); err == nil {
|
||
return DURATION, buf.String(), val
|
||
}
|
||
|
||
// Otherwise return as a regular identifier.
|
||
return tok, buf.String(), val
|
||
|
||
}
|
||
|
||
// scanThing consumes the current rune and all contiguous ident runes.
|
||
func (s *scanner) scanThing(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
tok = THING
|
||
|
||
var tbv string
|
||
var idv interface{}
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Read passed in runes
|
||
for _, ch := range chp {
|
||
buf.WriteRune(ch)
|
||
}
|
||
|
||
if tok, tbv, _ = s.part(); tok == ILLEGAL {
|
||
buf.WriteString(tbv)
|
||
return ILLEGAL, buf.String(), val
|
||
} else {
|
||
buf.WriteString(tbv)
|
||
}
|
||
|
||
if ch := s.next(); ch == ':' {
|
||
buf.WriteRune(ch)
|
||
} else {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
|
||
if tok, lit, idv = s.part(); tok == ILLEGAL {
|
||
buf.WriteString(lit)
|
||
return ILLEGAL, buf.String(), val
|
||
} else {
|
||
buf.WriteString(lit)
|
||
}
|
||
|
||
return THING, buf.String(), NewThing(tbv, idv)
|
||
|
||
}
|
||
|
||
func (s *scanner) scanModel(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
var com bool
|
||
var dot bool
|
||
|
||
var tbv string
|
||
var min float64 = 0
|
||
var inc float64 = 0
|
||
var max float64 = 0
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Read passed in runes
|
||
for _, ch := range chp {
|
||
buf.WriteRune(ch)
|
||
}
|
||
|
||
if tok, tbv, _ = s.part(); tok == ILLEGAL {
|
||
buf.WriteString(tbv)
|
||
return ILLEGAL, buf.String(), val
|
||
} else {
|
||
buf.WriteString(tbv)
|
||
}
|
||
|
||
if ch := s.next(); ch == ':' {
|
||
buf.WriteRune(ch)
|
||
} else {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
|
||
if ch := s.next(); isSignal(ch) {
|
||
tok, lit, _ = s.scanSignal(ch)
|
||
buf.WriteString(lit)
|
||
max, _ = strconv.ParseFloat(lit, 64)
|
||
} else {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
|
||
if ch := s.next(); ch == ',' {
|
||
com = true
|
||
buf.WriteRune(ch)
|
||
if ch := s.next(); isSignal(ch) {
|
||
tok, lit, _ = s.scanSignal(ch)
|
||
buf.WriteString(lit)
|
||
inc, _ = strconv.ParseFloat(lit, 64)
|
||
} else {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
} else {
|
||
s.undo()
|
||
}
|
||
|
||
if ch := s.next(); ch == '.' {
|
||
dot = true
|
||
buf.WriteRune(ch)
|
||
if ch := s.next(); ch == '.' {
|
||
buf.WriteRune(ch)
|
||
if ch := s.next(); isSignal(ch) {
|
||
tok, lit, _ = s.scanSignal(ch)
|
||
buf.WriteString(lit)
|
||
min = max
|
||
max, _ = strconv.ParseFloat(lit, 64)
|
||
} else {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
} else {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
} else {
|
||
s.undo()
|
||
}
|
||
|
||
if ch := s.next(); ch == '|' {
|
||
buf.WriteRune(ch)
|
||
} else {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
|
||
// If the minimum value is the
|
||
// same as the maximum value then
|
||
// error, as there is no ability
|
||
// to increment or decrement.
|
||
|
||
if min == max {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
|
||
// If we have a comma, but the
|
||
// value is below zero, we will
|
||
// error as this will cause an
|
||
// infinite loop in db.
|
||
|
||
if com == true && inc <= 0 {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
|
||
// If we have a min, and a max
|
||
// with .. notation, but no `inc`
|
||
// is specified, set the `inc` to
|
||
// a default of `1`.
|
||
|
||
if dot == true && inc <= 0 {
|
||
inc = 1
|
||
}
|
||
|
||
// If we have a comma, but no
|
||
// max value is specified then
|
||
// error, as we need a max with
|
||
// incrementing integer ids.
|
||
|
||
if com == true && dot == false {
|
||
return ILLEGAL, buf.String(), val
|
||
}
|
||
|
||
return MODEL, buf.String(), NewModel(tbv, min, inc, max)
|
||
|
||
}
|
||
|
||
func (s *scanner) scanSignal(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Read passed in runes
|
||
for _, ch := range chp {
|
||
buf.WriteRune(ch)
|
||
}
|
||
|
||
// Read subsequent characters
|
||
for {
|
||
if ch := s.next(); ch == eof {
|
||
break
|
||
} else if isNumber(ch) {
|
||
buf.WriteRune(ch)
|
||
} else if ch == '.' {
|
||
if s.next() == '.' {
|
||
s.undo()
|
||
s.undo()
|
||
break
|
||
} else {
|
||
s.undo()
|
||
buf.WriteRune(ch)
|
||
}
|
||
} else {
|
||
s.undo()
|
||
break
|
||
}
|
||
}
|
||
|
||
return NUMBER, buf.String(), nil
|
||
|
||
}
|
||
|
||
func (s *scanner) scanNumber(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
tok = NUMBER
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Read passed in runes
|
||
for _, ch := range chp {
|
||
buf.WriteRune(ch)
|
||
}
|
||
|
||
// Read subsequent characters
|
||
for {
|
||
if ch := s.next(); ch == eof {
|
||
break
|
||
} else if isNumber(ch) {
|
||
buf.WriteRune(ch)
|
||
} else if isLetter(ch) {
|
||
if tok == NUMBER || tok == DOUBLE || tok == DURATION {
|
||
tok = IDENT
|
||
buf.WriteRune(ch)
|
||
switch ch {
|
||
case 'e', 'E':
|
||
if chn := s.next(); chn == '+' {
|
||
tok = DOUBLE
|
||
buf.WriteRune(chn)
|
||
} else if ch == '-' {
|
||
tok = DOUBLE
|
||
buf.WriteRune(chn)
|
||
} else {
|
||
s.undo()
|
||
}
|
||
case 's', 'h', 'd', 'w':
|
||
tok = DURATION
|
||
case 'n', 'u', 'µ', 'm':
|
||
if chn := s.next(); chn == 's' {
|
||
tok = DURATION
|
||
buf.WriteRune(chn)
|
||
} else if ch == 'm' {
|
||
tok = DURATION
|
||
s.undo()
|
||
} else {
|
||
s.undo()
|
||
}
|
||
}
|
||
} else {
|
||
tok = IDENT
|
||
buf.WriteRune(ch)
|
||
}
|
||
} else if ch == '.' {
|
||
if tok == DOUBLE {
|
||
tok = IDENT
|
||
}
|
||
if tok == NUMBER {
|
||
tok = DOUBLE
|
||
}
|
||
buf.WriteRune(ch)
|
||
} else {
|
||
s.undo()
|
||
break
|
||
}
|
||
}
|
||
|
||
return tok, buf.String(), nil
|
||
|
||
}
|
||
|
||
func (s *scanner) scanString(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
beg := chp[0]
|
||
end := beg
|
||
|
||
if beg == '"' {
|
||
end = '"'
|
||
}
|
||
|
||
if beg == '`' {
|
||
end = '`'
|
||
}
|
||
|
||
if beg == '⟨' {
|
||
end = '⟩'
|
||
}
|
||
|
||
tok = STRING
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Ignore passed in runes
|
||
|
||
// Read subsequent characters
|
||
for {
|
||
if ch := s.next(); ch == end {
|
||
break
|
||
} else if ch == eof {
|
||
return ILLEGAL, buf.String(), val
|
||
} else if ch == '\n' {
|
||
tok = REGION
|
||
buf.WriteRune(ch)
|
||
} else if ch == '\r' {
|
||
tok = REGION
|
||
buf.WriteRune(ch)
|
||
} else if ch == '\\' {
|
||
switch chn := s.next(); chn {
|
||
default:
|
||
buf.WriteRune(chn)
|
||
case 'b':
|
||
continue
|
||
case 't':
|
||
tok = REGION
|
||
buf.WriteRune('\t')
|
||
case 'r':
|
||
tok = REGION
|
||
buf.WriteRune('\r')
|
||
case 'n':
|
||
tok = REGION
|
||
buf.WriteRune('\n')
|
||
}
|
||
} else {
|
||
buf.WriteRune(ch)
|
||
}
|
||
}
|
||
|
||
if val, err := time.Parse(RFCDate, buf.String()); err == nil {
|
||
return DATE, buf.String(), val.UTC()
|
||
}
|
||
|
||
if val, err := time.Parse(RFCTime, buf.String()); err == nil {
|
||
return TIME, buf.String(), val.UTC()
|
||
}
|
||
|
||
return tok, buf.String(), val
|
||
|
||
}
|
||
|
||
func (s *scanner) scanRegexp(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
tok = IDENT
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Ignore passed in runes
|
||
|
||
// Read subsequent characters
|
||
for {
|
||
if ch := s.next(); ch == chp[0] {
|
||
break
|
||
} else if ch == eof {
|
||
return ILLEGAL, buf.String(), val
|
||
} else if ch == '\\' {
|
||
chn := s.next()
|
||
buf.WriteRune(ch)
|
||
buf.WriteRune(chn)
|
||
} else {
|
||
buf.WriteRune(ch)
|
||
}
|
||
}
|
||
|
||
if _, err := regexp.Compile(buf.String()); err == nil {
|
||
return REGEX, buf.String(), nil
|
||
}
|
||
|
||
return tok, buf.String(), val
|
||
|
||
}
|
||
|
||
func (s *scanner) scanObject(chp ...rune) (tok Token, lit string, val interface{}) {
|
||
|
||
beg := chp[0]
|
||
end := beg
|
||
sub := 0
|
||
qut := 0
|
||
|
||
if beg == '{' {
|
||
end = '}'
|
||
tok = JSON
|
||
}
|
||
|
||
if beg == '[' {
|
||
end = ']'
|
||
tok = ARRAY
|
||
}
|
||
|
||
// Create a buffer
|
||
var buf bytes.Buffer
|
||
|
||
// Read passed in runes
|
||
for _, ch := range chp {
|
||
buf.WriteRune(ch)
|
||
}
|
||
|
||
// Read subsequent characters
|
||
for {
|
||
if ch := s.next(); ch == end && sub == 0 && qut == 0 {
|
||
buf.WriteRune(ch)
|
||
break
|
||
} else if ch == beg {
|
||
sub++
|
||
buf.WriteRune(ch)
|
||
} else if ch == end {
|
||
sub--
|
||
buf.WriteRune(ch)
|
||
} else if ch == eof {
|
||
return ILLEGAL, buf.String(), val
|
||
} else if ch == '"' {
|
||
if qut == 0 {
|
||
qut++
|
||
} else {
|
||
qut--
|
||
}
|
||
buf.WriteRune(ch)
|
||
} else if ch == '\\' {
|
||
switch chn := s.next(); chn {
|
||
default:
|
||
return ILLEGAL, buf.String(), val
|
||
case 'b', 't', 'r', 'n', 'f', 'u', '"', '\\':
|
||
buf.WriteRune(ch)
|
||
buf.WriteRune(chn)
|
||
}
|
||
} else {
|
||
buf.WriteRune(ch)
|
||
}
|
||
}
|
||
|
||
return tok, buf.String(), val
|
||
|
||
}
|
||
|
||
func (s *scanner) part() (tok Token, lit string, val interface{}) {
|
||
|
||
if ch := s.next(); isLetter(ch) {
|
||
tok, lit, _ = s.scanIdent(ch)
|
||
} else if isNumber(ch) {
|
||
tok, lit, _ = s.scanNumber(ch)
|
||
} else if ch == '`' {
|
||
tok, lit, _ = s.scanSection(ch)
|
||
} else if ch == '⟨' {
|
||
tok, lit, _ = s.scanSection(ch)
|
||
} else {
|
||
s.undo()
|
||
tok = ILLEGAL
|
||
}
|
||
|
||
if tok != IDENT && tok != NUMBER && tok != DOUBLE {
|
||
tok = ILLEGAL
|
||
}
|
||
|
||
if val == nil {
|
||
val = lit
|
||
}
|
||
|
||
return
|
||
|
||
}
|
||
|
||
// next reads the next rune from the bufferred reader.
|
||
// Returns the rune(0) if an error occurs (or io.EOF is returned).
|
||
func (s *scanner) next() rune {
|
||
|
||
if len(s.a) > 0 {
|
||
var r rune
|
||
r, s.a = s.a[len(s.a)-1], s.a[:len(s.a)-1]
|
||
s.b = append(s.b, r)
|
||
return r
|
||
}
|
||
|
||
r, _, err := s.r.ReadRune()
|
||
if err != nil {
|
||
return eof
|
||
}
|
||
s.b = append(s.b, r)
|
||
return r
|
||
|
||
}
|
||
|
||
// undo places the previously read rune back on the reader.
|
||
func (s *scanner) undo() {
|
||
|
||
if len(s.b) > 0 {
|
||
var r rune
|
||
r, s.b = s.b[len(s.b)-1], s.b[:len(s.b)-1]
|
||
s.a = append(s.a, r)
|
||
return
|
||
}
|
||
|
||
_ = s.r.UnreadRune()
|
||
|
||
}
|
||
|
||
// isBlank returns true if the rune is a space, tab, or newline.
|
||
func isBlank(ch rune) bool {
|
||
return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r'
|
||
}
|
||
|
||
// isNumber returns true if the rune is a number.
|
||
func isNumber(ch rune) bool {
|
||
return (ch >= '0' && ch <= '9')
|
||
}
|
||
|
||
// isSignal returns true if the rune is a number.
|
||
func isSignal(ch rune) bool {
|
||
return (ch >= '0' && ch <= '9') || ch == '-' || ch == '+'
|
||
}
|
||
|
||
// isLetter returns true if the rune is a letter.
|
||
func isLetter(ch rune) bool {
|
||
return (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || ch == 'µ'
|
||
}
|
||
|
||
// isIdentChar returns true if the rune is allowed in a IDENT.
|
||
func isIdentChar(ch rune) bool {
|
||
return isLetter(ch) || isNumber(ch) || ch == '_'
|
||
}
|
||
|
||
// isThingChar returns true if the rune is allowed in a THING.
|
||
func isThingChar(ch rune) bool {
|
||
return isLetter(ch) || isNumber(ch) || ch == '_'
|
||
}
|
||
|
||
// isArrayChar returns true if the rune is allowed in an ARRAY.
|
||
func isArrayChar(ch rune) bool {
|
||
return ch == '[' || ch == ']'
|
||
}
|
||
|
||
// isExprsChar returns true if the rune is allowed in a IDENT.
|
||
func isExprsChar(ch rune) bool {
|
||
return isLetter(ch) || isNumber(ch) || ch == '.' || ch == '_' || ch == '*' || ch == '$'
|
||
}
|
||
|
||
// eof represents a marker rune for the end of the reader.
|
||
var eof = rune(0)
|