Module
Parser combinators library designed for Deno, but also works on browsers and Node.js.
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/** * Parse a single "space" character. * * space()(" ").output === " "; */export function space(): IParser<" ", ErrorKind.Space, string> { return <C>( input: string, context: C = Object.create(null), ): Result<string, " ", ErrorKind.Space, C> => { if (input.charCodeAt(0) === 32) { return { ok: true, input: input.slice(1), output: " ", context, }; } else { return { ok: false, input, error: ErrorKind.Space, context, }; } };}
/** * Parse a single "carriage return" character. * * cr()("\r").output === "\r"; */export function cr(): IParser<"\r", ErrorKind.CarriageReturn, string> { return <C>( input: string, context: C = Object.create(null), ): Result<string, "\r", ErrorKind.CarriageReturn, C> => { if (input.charCodeAt(0) === 13) { return { ok: true, input: input.slice(1), output: "\r", context, }; } else { return { ok: false, input, error: ErrorKind.CarriageReturn, context, }; } };}
/** * Parse a single "line feed" character. * * lf()("\n").output === "\n"; */export function lf(): IParser<"\n", ErrorKind.LineFeed, string> { return <C>( input: string, context: C = Object.create(null), ): Result<string, "\n", ErrorKind.LineFeed, C> => { if (input.charCodeAt(0) === 10) { return { ok: true, input: input.slice(1), output: "\n", context, }; } else { return { ok: false, input, error: ErrorKind.LineFeed, context, }; } };}
/** * Parse paired "carriage return - line feed" characters. * * crlf()("\r\n").output === "\r\n"; */export function crlf(): IParser< "\r\n", ErrorKind.CarriageReturnLineFeed, string> { return <C>( input: string, context: C = Object.create(null), ): Result<string, "\r\n", ErrorKind.CarriageReturnLineFeed, C> => { if (input.charCodeAt(0) === 13 && input.charCodeAt(1) === 10) { return { ok: true, input: input.slice(2), output: "\r\n", context, }; } else { return { ok: false, input, error: ErrorKind.CarriageReturnLineFeed, context, }; } };}
/** * Parse linebreak, which can be "\n" or "\r\n". * * linebreak()("\n").output === "\n"; * linebreak()("\r\n").output === "\r\n"; */export function linebreak(): IParser< "\n" | "\r\n", ErrorKind.Linebreak, string> { return <C>( input: string, context: C = Object.create(null), ): Result<string, "\n" | "\r\n", ErrorKind.Linebreak, C> => { const firstCharCode = input.charCodeAt(0); if (firstCharCode === 10) { return { ok: true, input: input.slice(1), output: "\n", context, }; } else if (firstCharCode === 13 && input.charCodeAt(1) === 10) { return { ok: true, input: input.slice(2), output: "\r\n", context, }; } else { return { ok: false, input, error: ErrorKind.Linebreak, context, }; } };}
/** * Parse a single "tab" character. * * tab()("\t").output === "\t"; */export function tab(): IParser<"\t", ErrorKind.Tab, string> { return <C>( input: string, context: C = Object.create(null), ): Result<string, "\t", ErrorKind.Tab, C> => { if (input.charCodeAt(0) === 9) { return { ok: true, input: input.slice(1), output: "\t", context, }; } else { return { ok: false, input, error: ErrorKind.Tab, context, }; } };}
/** * Unicode whitespace. * * @see https://www.unicode.org/Public/UCD/latest/ucd/PropList.txt */type Whitespace = | "\u0009" | "\u000A" | "\u000B" | "\u000C" | "\u000D" | "\u0020" | "\u0085" | "\u00A0" | "\u1680" | "\u2000" | "\u2001" | "\u2002" | "\u2003" | "\u2004" | "\u2005" | "\u2006" | "\u2007" | "\u2008" | "\u2009" | "\u200A" | "\u2028" | "\u2029" | "\u202F" | "\u205F" | "\u3000";const UNICODE_WHITESPACE = [ 0x0009, 0x000A, 0x000B, 0x000C, 0x000D, 0x0020, 0x0085, 0x00A0, 0x1680, 0x2000, 0x2001, 0x2002, 0x2003, 0x2004, 0x2005, 0x2006, 0x2007, 0x2008, 0x2009, 0x200A, 0x2028, 0x2029, 0x202F, 0x205F, 0x3000,];
/** * Parse a Unicode Whitespace character. * * whitespace()("\v").output === "\v"; */export function whitespace(): IParser< Whitespace, ErrorKind.Whitespace, string> { return <C>( input: string, context: C = Object.create(null), ): Result<string, Whitespace, ErrorKind.Whitespace, C> => { if (UNICODE_WHITESPACE.includes(input.charCodeAt(0))) { return { ok: true, input: input.slice(1), output: input[0] as Whitespace, context, }; } else { return { ok: false, input, error: ErrorKind.Whitespace, context, }; } };}
/** * Trim heading whitespace characters by calling `String.prototype.trim`, * then pass the trimmed input to embedded parser. * * trim(alpha())(" \f\r\n\ta").output === "a"; * * @param parser embedded parser */export function trim<O, E>( parser: IParser<O, E, string>,): IParser<O, E, string> { function parse<C>( input: string, context: C = Object.create(null), ): Result<string, O, E, C> { return parse.parser(input.trimStart(), context); } parse.parser = parser;
return parse;}
/** * Expect input is empty, otherwise it produces a parsing error. * * Input type can be `string` or `Uint8Array`. * * eof()("").ok === true; * eof()(Uint8Array.of()).ok === true; */export function eof(): IParser<undefined, ErrorKind.EndOfFile, Input> { return <C>( input: Input, context: C = Object.create(null), ): Result<Input, undefined, ErrorKind.EndOfFile, C> => { if (input.length === 0) { return { ok: true, input, output: undefined, context, }; } else { return { ok: false, input, error: ErrorKind.EndOfFile, context, }; } };}