Files
genieacs/lib/common/expression-parser.js
T
Zaid Abdulla 1e41c72d60 Convert backend code to ES modules
Bundling code now with Rollup for its flat bundling and tree shaking
support. Front end code still goes through Webpack for browser support.
2019-02-04 23:47:54 -08:00

380 lines
9.4 KiB
JavaScript

"use strict";
import parsimmon from "parsimmon";
// Turn escaped characters into real ones (e.g. "\\n" becomes "\n").
function interpretEscapes(str) {
const escapes = {
b: "\b",
f: "\f",
n: "\n",
r: "\r",
t: "\t"
};
return str.replace(/\\(u[0-9a-fA-F]{4}|[^u])/, (_, escape) => {
const type = escape.charAt(0);
const hex = escape.slice(1);
if (type === "u") return String.fromCharCode(parseInt(hex, 16));
if (escapes.hasOwnProperty(type)) return escapes[type];
return type;
});
}
export function map(exp, callback) {
if (!Array.isArray(exp)) return callback(exp);
let clone;
for (let i = 1; i < exp.length; ++i) {
const sub = map(exp[i], callback);
if (sub !== exp[i]) {
clone = clone || exp.slice();
clone[i] = sub;
}
}
return callback(clone || exp);
}
function binaryLeft(operatorsParser, nextParser) {
return parsimmon.seqMap(
nextParser,
parsimmon.seq(operatorsParser, nextParser).many(),
(first, rest) =>
rest.reduce((acc, ch) => {
const [op, another] = ch;
if (Array.isArray(acc) && op === acc[0]) return acc.concat([another]);
if (Array.isArray(another) && op === another[0])
return [op, acc].concat(another.slice(1));
return [op, acc, another];
}, first)
);
}
const lang = parsimmon.createLanguage({
ComparisonOperator: function() {
return parsimmon
.alt(
parsimmon.string(">="),
parsimmon.string("<>"),
parsimmon.string("<="),
parsimmon.string("="),
parsimmon.string(">"),
parsimmon.string("<")
)
.skip(parsimmon.optWhitespace);
},
LikeOperator: function() {
return parsimmon
.alt(
parsimmon
.regexp(/like/i)
.result("LIKE")
.desc("LIKE"),
parsimmon
.regexp(/not\s+like/i)
.result("NOT LIKE")
.desc("NOT LIKE")
)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace);
},
IsNullOperator: function() {
return parsimmon
.alt(
parsimmon
.regexp(/is\s+null/i)
.result("IS NULL")
.desc("IS NULL"),
parsimmon
.regexp(/is\s+not\s+null/i)
.result("IS NOT NULL")
.desc("IS NOT NULL")
)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace);
},
NotOperator: function() {
return parsimmon
.regexp(/not/i)
.result("NOT")
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("NOT");
},
AndOperator: function() {
return parsimmon
.regexp(/and/i)
.result("AND")
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("AND");
},
OrOperator: function() {
return parsimmon
.regexp(/or/i)
.result("OR")
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.desc("OR");
},
Parameter: function(r) {
return parsimmon
.alt(
parsimmon.regexp(/[a-zA-Z0-9_.*-]+/),
r.Expression.wrap(
parsimmon.string("{").skip(parsimmon.optWhitespace),
parsimmon.string("}")
)
)
.atLeast(1)
.map(x => ["PARAM", x.length > 1 ? ["||"].concat(x) : x[0]])
.skip(parsimmon.optWhitespace)
.desc("parameter");
},
StringValueSql: function() {
return parsimmon
.regexp(/'([^']*)'/, 1)
.atLeast(1)
.skip(parsimmon.optWhitespace)
.map(s => s.join("'"))
.desc("string");
},
StringValueJs: function() {
return parsimmon
.regexp(/"((?:\\.|.)*?)"/, 1)
.skip(parsimmon.optWhitespace)
.map(interpretEscapes)
.desc("string");
},
NumberValue: function() {
return parsimmon
.regexp(/-?(0|[1-9][0-9]*)([.][0-9]+)?([eE][+-]?[0-9]+)?/)
.skip(parsimmon.optWhitespace)
.map(Number)
.desc("number");
},
BooleanValue: function() {
return parsimmon
.alt(
parsimmon
.regexp(/true/i)
.result(true)
.desc("TRUE"),
parsimmon
.regexp(/false/i)
.result(false)
.desc("FALSE")
)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace);
},
NullValue: function() {
return parsimmon
.regexp(/null/i)
.notFollowedBy(parsimmon.regexp(/[a-zA-Z0-9_]/))
.skip(parsimmon.optWhitespace)
.result(null)
.desc("NULL");
},
FuncValue: function(r) {
return parsimmon.seqMap(
parsimmon
.regexp(/([a-zA-Z0-9_]+)/, 1)
.skip(parsimmon.optWhitespace)
.desc("function"),
r.ValueExpression.sepBy(
parsimmon.string(",").skip(parsimmon.optWhitespace)
).wrap(
parsimmon.string("(").skip(parsimmon.optWhitespace),
parsimmon.string(")").skip(parsimmon.optWhitespace)
),
(f, args) => ["FUNC", f.toUpperCase()].concat(args)
);
},
Value: function(r) {
return parsimmon.alt(
r.NullValue,
r.BooleanValue,
r.NumberValue,
r.StringValueSql,
r.StringValueJs,
r.FuncValue
);
},
ValueExpression: function(r) {
return binaryLeft(
parsimmon.string("||").skip(parsimmon.optWhitespace),
binaryLeft(
parsimmon
.alt(parsimmon.string("+"), parsimmon.string("-"))
.skip(parsimmon.optWhitespace),
binaryLeft(
parsimmon
.alt(parsimmon.string("*"), parsimmon.string("/"))
.skip(parsimmon.optWhitespace),
parsimmon.alt(
r.Value,
r.Parameter,
r.Expression.wrap(
parsimmon.string("(").skip(parsimmon.optWhitespace),
parsimmon.string(")").skip(parsimmon.optWhitespace)
)
)
)
)
);
},
Comparison: function(r) {
return parsimmon.alt(
parsimmon.seqMap(r.ValueExpression, r.IsNullOperator, (p, o) => [o, p]),
parsimmon.seqMap(
r.ValueExpression,
r.ComparisonOperator,
r.ValueExpression,
(p, o, v) => [o, p, v]
),
parsimmon.seqMap(
r.ValueExpression,
r.LikeOperator,
r.ValueExpression.skip(
parsimmon
.regexp(/escape/i)
.result("ESCAPE")
.skip(parsimmon.whitespace)
.desc("ESCAPE")
),
r.ValueExpression,
(a, b, c, d) => [b, a, c, d]
),
parsimmon.seqMap(
r.ValueExpression,
r.LikeOperator,
r.ValueExpression,
(a, b, c) => [b, a, c]
)
);
},
Expression: function(r) {
function unary(operatorsParser, nextParser) {
return parsimmon.seq(operatorsParser, nextParser).or(nextParser);
}
return binaryLeft(
r.OrOperator,
binaryLeft(
r.AndOperator,
unary(r.NotOperator, r.Comparison.or(r.ValueExpression))
)
).trim(parsimmon.optWhitespace);
}
});
export function parse(str) {
if (!str) return null;
return lang.Expression.tryParse(str);
}
export function stringify(exp, level = 0) {
if (!Array.isArray(exp)) return JSON.stringify(exp);
const opLevels = {
OR: 10,
AND: 11,
NOT: 12,
"=": 20,
"<>": 20,
">": 20,
">=": 20,
"<": 20,
"<=": 20,
LIKE: 20,
"NOT LIKE": 20,
"IS NULL": 20,
"IS NOT NULL": 20,
"||": 30,
"+": 31,
"-": 31,
"*": 32,
"/": 32
};
const op = exp[0].toUpperCase();
function wrap(e) {
if (opLevels[op] <= level) return `(${e})`;
else return e;
}
if (op === "FUNC") {
return wrap(
`${exp[1]}(${exp
.slice(2)
.map(e => stringify(e))
.join(", ")})`
);
} else if (op === "PARAM") {
if (typeof exp[1] === "string") {
return wrap(exp[1]);
} else if (Array.isArray(exp[1]) && exp[1][0] === "||") {
return wrap(
exp[1]
.slice(1)
.map(p => {
if (typeof p === "string") return p;
else return `{${stringify(p)}}`;
})
.join("")
);
} else {
return wrap(`{${stringify(exp[1])}}`);
}
} else if (op === "IS NULL" || op === "IS NOT NULL") {
return wrap(`${stringify(exp[1], opLevels[op])} ${op}`);
} else if (op === "LIKE" || op === "NOT LIKE") {
if (exp[3]) {
return wrap(
`${stringify(exp[1], opLevels[op])} ${op} ${stringify(
exp[2],
opLevels[op]
)} ESCAPE ${stringify(exp[3], opLevels[op])}`
);
} else {
return wrap(
`${stringify(exp[1], opLevels[op])} ${op} ${stringify(
exp[2],
opLevels[op]
)}`
);
}
} else if (op in opLevels) {
const parts = exp.slice(1).map((e, i) => {
return stringify(e, opLevels[exp[0]] + Math.min(i - 1, 0));
});
if (op === "NOT") return wrap(`${op} ${parts[0]}`);
else return wrap(parts.join(` ${op} `));
} else {
throw new Error(`Unrecognized operator ${exp[0]}`);
}
}
export function parseLikePattern(pat, esc) {
const chars = pat.split("");
for (let i = 0; i < chars.length; ++i) {
const c = chars[i];
if (c === esc) {
chars[i] = chars[i + 1] || "";
chars[i + 1] = "";
} else if (c === "_") {
chars[i] = "\\_";
} else if (c === "%") {
chars[i] = "\\%";
while (chars[i + 1] === "%") chars[++i] = "";
}
}
return chars.filter(c => c);
}