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minodisk/parser.ts

Created October 19, 2022 13:43
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  1. minodisk created this gist Oct 19, 2022.
    58 changes: 58 additions & 0 deletions parser.ts
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,58 @@
    import { formatters } from "sql-formatter";
    import type { Token as OrigToken } from "sql-formatter/lib/src/lexer/token";

    export type Token = OrigToken & {
    line: number;
    column: number;
    };

    export const createParser = () => {
    const tokenizer = formatters.bigquery.prototype.tokenizer();

    const breaks = (precedingWhitespace: string) => {
    let newLines = 0;
    let charactersBeforeLastLine = 0;
    for (let i = 0; i < precedingWhitespace.length; i++) {
    const char = precedingWhitespace[i];
    if (char === "\n") {
    newLines += 1;
    charactersBeforeLastLine = i + 1;
    }
    }
    return { newLines, charactersBeforeLastLine };
    };

    return {
    parse(query: string): Array<Token> {
    const tokens = tokenizer.tokenize(query, {});
    let line = 0;
    let caret = 0;
    let lineStart = 0;
    return tokens.map((token) => {
    if (!token.precedingWhitespace) {
    const t = {
    ...token,
    line,
    column: token.start - lineStart,
    };
    caret += token.raw.length;
    return t;
    }
    const { newLines, charactersBeforeLastLine } = breaks(
    token.precedingWhitespace
    );
    line += newLines;
    if (newLines) {
    lineStart = caret + charactersBeforeLastLine;
    }
    const t = {
    ...token,
    line,
    column: token.start - lineStart,
    };
    caret += token.precedingWhitespace.length + token.raw.length;
    return t;
    });
    },
    };
    };