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Diffstat (limited to 'users/wpcarro/slx.js/index.js')
| -rw-r--r-- | users/wpcarro/slx.js/index.js | 455 |
1 files changed, 455 insertions, 0 deletions
diff --git a/users/wpcarro/slx.js/index.js b/users/wpcarro/slx.js/index.js new file mode 100644 index 000000000000..3729978c75ef --- /dev/null +++ b/users/wpcarro/slx.js/index.js @@ -0,0 +1,455 @@ +function select(query, xs, config) { + // naive optimizations + if (query === '' || xs === []) { + return xs; + } + + const predicate = compile(parse(query, config), config); + return xs.filter(predicate); +} + +function compile(ast, config) { + if (ast.type === 'CONJUNCTION') { + const lhs = compile(ast.lhs, compile); + const rhs = compile(ast.rhs, compile); + + if (ast.joint === 'AND') { + return function(x) { + return lhs(x) && rhs(x); + }; + } + if (ast.joint === 'OR') { + return function(x) { + return lhs(x) || rhs(x); + }; + } + } + if (ast.type === 'DATE_SELECTION') { + if (ast.key === 'before') { + return function(row) { + let t = new Date(); + if (ast.val === 'yesterday') { + t.setDate(t.getDate() - 1); + console.log(t); + } + // MM/DD/YYYY + else { + t = new Date(ast.val); + } + return row[config.dateKey] < t; + }; + } + if (ast.key === 'after') { + return function(row) { + let t = new Date(); + if (ast.val === 'yesterday') { + t.setDate(t.getDate() - 1); + console.log(t); + } + // MM/DD/YYYY + else { + t = new Date(ast.val); + } + return row[config.dateKey] > t; + }; + } + } + if (ast.type === 'COMPARE_SELECTION') { + const f = compile(ast.val, config); + + let compare = null; + if (ast.operator === 'EQ') { compare = (x, y) => x === y; } + if (ast.operator === 'LT') { compare = (x, y) => x < y; } + if (ast.operator === 'GT') { compare = (x, y) => x > y; } + if (ast.operator === 'LTE') { compare = (x, y) => x <= y; } + if (ast.operator === 'GTE') { compare = (x, y) => x >= y; } + + return function(row) { + return ast.negate ? !compare(row[ast.key], ast.val) : compare(row[ast.key], ast.val); + }; + } + if (ast.type === 'SELECTION') { + const f = compile(ast.val, config); + return function(row) { + return ast.negate ? !f(row[ast.key]) : f(row[ast.key]); + }; + } + if (ast.type === 'MATCH_ALL') { + if (ast.matchType === 'STRING') { + return function(row) { + return Object.values(row).some(x => { + if (config.caseSensitive) { + return x === ast.val; + } else { + return x.toLowerCase() === ast.val.toLowerCase(); + } + }) + }; + } + if (ast.matchType === 'REGEX') { + return function(row) { + return Object.values(row).some(x => ast.val.test(x)); + }; + } + } + if (ast.type === 'GROUPING') { + return compile(ast.content); + } + if (ast.type === 'STRING') { + return function(x) { + if (config.caseSensitive) { + return x === ast.val; + } else { + return x.toLowerCase() === ast.val.toLowerCase(); + } + }; + } + if (ast.type === 'REGEX') { + return function(x) { + return ast.val.test(x); + }; + } +} + +// A "selection" without a "$column:" prefix should fuzzy-search all columns. +// +// conjunction -> selection ( ( "AND" | "OR" )? selection )* ; +// selection -> "-"? COLUMN ":" ( regex | string ) | regex ; +// regex -> [_-a-zA-Z0-9] | "/" [ _-a-zA-Z0-9] "/" | string ; +// string -> "\"" [ _-a-zA-Z0-9] "\"" ; + +// Whatever characters are valid for a JS regex. +const ATOM_REGEX = /[-_.\[\]a-zA-Z0-9*+^$]/; + +function tokenize(x) { + const result = []; + let i = 0; + while (i < x.length) { + if (x[i] === ' ') { + i += 1; + while (i < x.length && x[i] === ' ') { + i += 1; + } + result.push(['WHITESPACE', null]); + continue; + } + if (x[i] === '-') { + result.push(['NEGATE', null]); + i += 1; + continue; + } + // Tokenize numbers (i.e. integers, floats). + if (/[0-9]/.test(x[i])) { + let curr = x[i]; + i += 1; + while (i < x.length && /[0-9]/.test(x[i])) { + curr += x[i]; + i += 1; + } + result.push(['NUMBER', parseFloat(curr)]); + continue; + } + if (ATOM_REGEX.test(x[i])) { + let curr = x[i]; + i += 1; + while (i < x.length && ATOM_REGEX.test(x[i])) { + curr += x[i]; + i += 1; + } + result.push(['ATOM', curr]); + continue; + } + if (x[i] === '=') { + result.push(['COMPARE', 'EQ']); + i += 1; + continue; + } + if (x[i] === '<' && i + 1 < x.length && x[i + 1] === '=') { + result.push(['COMPARE', 'LTE']); + i += 2; + continue; + } + if (x[i] === '<') { + result.push(['COMPARE', 'LT']); + i += 1; + continue; + } + if (x[i] === '>' && i + i < x.length && x[i + 1] === '=') { + result.push(['COMPARE', 'GTE']); + i += 2; + continue; + } + if (x[i] === '>') { + result.push(['COMPARE', 'GT']); + i += 1; + continue; + } + if (x[i] === ':') { + result.push(['COLON', null]); + i += 1; + continue; + } + if (x[i] === '(') { + result.push(['LPAREN', null]); + i += 1; + continue; + } + if (x[i] === ')') { + result.push(['RPAREN', null]); + i += 1; + continue; + } + if (x[i] === '/') { + let start = i; + let curr = ''; + i += 1; + while (i < x.length && x[i] !== '/') { + curr += x[i]; + i += 1; + } + // error + if (i >= x.length) { + throw `Tokenize Error: EOL while attempting to tokenize the regex beginning at column: ${start}`; + } + if (x[i] === '/') { + result.push(['REGEX', curr]); + i += 1; + } + continue; + } + if (x[i] === '"') { + let start = i; + let curr = ''; + i += 1; + while (i < x.length && x[i] !== '"') { + // continue on \" + if (x[i] === '\\' && x[i + 1] === '"') { + curr += '\"'; + i += 2; + } else { + curr += x[i]; + i += 1; + } + } + if (i >= x.length) { + throw `Tokenize Error: EOL while attempting to tokenize the string starting at column: ${start}`; + } + if (x[i] === '"') { + result.push(['STRING', curr]); + i += 1; + } + continue; + } + else { + i += 1; + } + } + return result; +} + +function expect(f, expectation, p) { + const [type, val] = p.tokens[p.i]; + if (f(type, val)) { + p.i += 1; + } else { + throw `Parse Error: expected ${expectation}, but got ${p.tokens[p.i]}; ${JSON.stringify(p)}` + } +} + +function matches(f, p) { + const [type, val] = p.tokens[p.i]; + if (f(type, val)) { + return true; + } + return false; +} + +function match(f, expectation, p) { + const [type, val] = p.tokens[p.i]; + if (f(type, val)) { + p.i += 1; + return val; + } + throw `Parse Error: expected ${expectation}, but got: ${p.tokens[p.i]}; ${JSON.stringify(p)}`; +} + +function skipWhitespace(p) { + while (p.i < p.tokens.length && matches((type, _) => type === 'WHITESPACE', p)) { + p.i += 1; + } +} + +function peekType(n, p) { + if (p.i + n < p.tokens.length) { + return p.tokens[p.i + n][0]; + } + return null; +} + +function parser(tokens) { + return { i: 0, tokens }; +} + +function parse(x, config) { + const tokens = tokenize(x); + const p = parser(tokens); + return conjunction(p, config); +} + +function conjunction(p, config) { + skipWhitespace(p); + + const lhs = selection(p, config); + skipWhitespace(p); + + // TODO(wpcarro): Consider re-architecting the parser to avoid smells like + // this. + if (peekType(0, p) === 'RPAREN') { + return lhs; + } + + if (p.i >= p.tokens.length) { + return lhs; + } + + let joint = 'AND'; + if (matches((type, val) => type === 'ATOM' && val === 'AND', p)) { + joint = 'AND'; + p.i += 1; + } else if (matches((type, val) => type === 'ATOM' && val === 'OR', p)) { + joint = 'OR'; + p.i += 1; + } + skipWhitespace(p); + const rhs = conjunction(p, config); + + return { + type: 'CONJUNCTION', + joint, + lhs, + rhs, + }; +} + +function selection(p, config) { + // column:value OR -column:value + if ((peekType(0, p) === 'ATOM' && peekType(1, p) === 'COLON') || + (peekType(0, p) === 'NEGATE' && peekType(1, p) === 'ATOM' && peekType(2, p) === 'COLON')) { + + let negate = false; + if (p.tokens[p.i][0] === 'NEGATE') { + negate = true; + p.i += 1; + } + + const key = match((type, _) => type === 'ATOM', 'a column label', p); + expect((type, val) => type === 'COLON', 'a colon', p); + + if (key === 'before' || key === 'after') { + const val = date(p); + return { + type: 'DATE_SELECTION', + key, + val, + }; + } else { + const val = value(p, config); + return { + type: 'SELECTION', + negate, + key, + val, + }; + } + } + // column<value OR -column<value + else if ((peekType(0, p) === 'ATOM' && peekType(1, p) === 'COMPARE') || + (peekType(0, p) === 'NEGATE' && peekType(1, p) === 'ATOM' && peekType(2, p) === 'COMPARE')) { + let negate = false; + if (p.tokens[p.i][0] === 'NEGATE') { + negate = true; + p.i += 1; + } + + const key = match((type, _) => type === 'ATOM', 'a column label', p); + const operator = match((type, _) => type === 'COMPARE', 'a comparison operator (i.e. "<", ">", "<=", ">=")', p); + const val = match((type, _) => type === 'NUMBER', 'a number', p); + + return { + type: 'COMPARE_SELECTION', + operator, + negate, + key, + val, + }; + } + else { + return matchAll(p, config); + } +} + +function matchAll(p, config) { + const [type, val] = p.tokens[p.i]; + + // Cast atoms into strings or regexes depending on the current config. + if (type === 'ATOM') { + p.i += 1; + if (config.preferRegex) { + const regex = config.caseSensitive ? new RegExp(val) : new RegExp(val, "i"); + return { type: 'MATCH_ALL', matchType: 'REGEX', val: regex }; + } else { + return { type: 'MATCH_ALL', matchType: 'STRING', val } + } + } + if (type === 'STRING') { + p.i += 1; + return { type: 'MATCH_ALL', matchType: 'STRING', val }; + } + if (type === 'REGEX') { + p.i += 1; + const regex = config.caseSensitive ? new RegExp(val) : new RegExp(val, "i"); + return { type: 'MATCH_ALL', matchType: 'REGEX', val: regex }; + } + if (type === 'LPAREN') { + p.i += 1; + const content = conjunction(p, config); + expect((type, _) => type === 'RPAREN', 'a closing parenthesis', p); + return { + type: 'GROUPING', + content, + }; + } + throw `Parse Error: Expected a regular expression or a string, but got: ${p.tokens[p.i]}; ${JSON.stringify(p)}`; +} + +function value(p, config) { + const [type, val] = p.tokens[p.i]; + + // Cast atoms into strings or regexes depending on the current config. + if (type === 'ATOM') { + p.i += 1; + if (config.preferRegex) { + const regex = config.caseSensitive ? new RegExp(val) : new RegExp(val, "i"); + return { type: 'REGEX', val: regex }; + } else { + return { type: 'STRING', val } + } + } + if (type === 'STRING') { + p.i += 1; + return { type, val }; + } + if (type === 'REGEX') { + p.i += 1; + const regex = config.caseSensitive ? new RegExp(val) : new RegExp(val, "i"); + return { type, val: regex }; + } + throw `Parse Error: Expected a regular expression or a string, but got: ${p.tokens[p.i]}; ${JSON.stringify(p)}`; +} + +function date(p) { + const [type, val] = p.tokens[p.i]; + p.i += 1; + + return val; +} |