43 lines
1,010 B
JavaScript
43 lines
1,010 B
JavaScript
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import {toString} from 'nlcst-to-string'
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// Factory to create a tokenizer based on a given `expression`.
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export function tokenizerFactory(childType, expression) {
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return tokenizer
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// A function that splits.
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function tokenizer(node) {
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const children = []
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const tokens = node.children
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const type = node.type
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let index = -1
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const lastIndex = tokens.length - 1
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let start = 0
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while (++index < tokens.length) {
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if (
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index === lastIndex ||
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(tokens[index].type === childType &&
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expression.test(toString(tokens[index])))
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) {
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const first = tokens[start]
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const last = tokens[index]
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const parent = {type, children: tokens.slice(start, index + 1)}
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if (first.position && last.position) {
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parent.position = {
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start: first.position.start,
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end: last.position.end
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}
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}
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children.push(parent)
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start = index + 1
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}
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}
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return children
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}
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}
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