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07c3cdd | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 | import { countColumn } from "./misc"
// STRING STREAM
// Fed to the mode parsers, provides helper functions to make
// parsers more succinct.
class StringStream {
constructor(string, tabSize) {
this.pos = this.start = 0
this.string = string
this.tabSize = tabSize || 8
this.lastColumnPos = this.lastColumnValue = 0
this.lineStart = 0
}
eol() {return this.pos >= this.string.length}
sol() {return this.pos == this.lineStart}
peek() {return this.string.charAt(this.pos) || undefined}
next() {
if (this.pos < this.string.length)
return this.string.charAt(this.pos++)
}
eat(match) {
let ch = this.string.charAt(this.pos)
let ok
if (typeof match == "string") ok = ch == match
else ok = ch && (match.test ? match.test(ch) : match(ch))
if (ok) {++this.pos; return ch}
}
eatWhile(match) {
let start = this.pos
while (this.eat(match)){}
return this.pos > start
}
eatSpace() {
let start = this.pos
while (/[\s\u00a0]/.test(this.string.charAt(this.pos))) ++this.pos
return this.pos > start
}
skipToEnd() {this.pos = this.string.length}
skipTo(ch) {
let found = this.string.indexOf(ch, this.pos)
if (found > -1) {this.pos = found; return true}
}
backUp(n) {this.pos -= n}
column() {
if (this.lastColumnPos < this.start) {
this.lastColumnValue = countColumn(this.string, this.start, this.tabSize, this.lastColumnPos, this.lastColumnValue)
this.lastColumnPos = this.start
}
return this.lastColumnValue - (this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0)
}
indentation() {
return countColumn(this.string, null, this.tabSize) -
(this.lineStart ? countColumn(this.string, this.lineStart, this.tabSize) : 0)
}
match(pattern, consume, caseInsensitive) {
if (typeof pattern == "string") {
let cased = str => caseInsensitive ? str.toLowerCase() : str
let substr = this.string.substr(this.pos, pattern.length)
if (cased(substr) == cased(pattern)) {
if (consume !== false) this.pos += pattern.length
return true
}
} else {
let match = this.string.slice(this.pos).match(pattern)
if (match && match.index > 0) return null
if (match && consume !== false) this.pos += match[0].length
return match
}
}
current(){return this.string.slice(this.start, this.pos)}
hideFirstChars(n, inner) {
this.lineStart += n
try { return inner() }
finally { this.lineStart -= n }
}
}
export default StringStream
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