Replace Filter class with expression structure

This is in order to be able to support UPPER() and LOWER() functions in
queries which are needed for case-insensitive search.
This commit is contained in:
Zaid Abdulla committed 2018-12-26 00:22:07 -08:00
1 parent 7194fcab44
commit c2d13e8364
25 files changed
+716 -578

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@@ -0,0 +1,308 @@
"use strict";
const parsimmon = require("parsimmon");
// Turn escaped characters into real ones (e.g. "\\n" becomes "\n").
function interpretEscapes(str) {
let escapes = {
b: "\b",
f: "\f",
n: "\n",
r: "\r",
t: "\t"
};
return str.replace(/\\(u[0-9a-fA-F]{4}|[^u])/, (_, escape) => {
let type = escape.charAt(0);
let hex = escape.slice(1);
if (type === "u") return String.fromCharCode(parseInt(hex, 16));
if (escapes.hasOwnProperty(type)) return escapes[type];
return type;
});
}
function map(exp, callback) {
if (!Array.isArray(exp)) return callback(exp);
let clone;
for (let i = 1; i < exp.length; ++i) {
let 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) => {
let [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);
},
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.Parameter, r.IsNullOperator, (p, o) => [o, p]),
parsimmon.seqMap(
r.ValueExpression,
r.ComparisonOperator,
r.ValueExpression,
(p, o, v) => [o, p, v]
)
);
},
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);
}
});
function parse(str) {
if (!str) return null;
return lang.Expression.tryParse(str);
}
function stringify(exp) {
if (!Array.isArray(exp)) return JSON.stringify(exp);
const opLevels = {
OR: 10,
AND: 11,
NOT: 12,
"=": 20,
"<>": 21,
">": 22,
">=": 23,
"<": 24,
"<=": 25,
"||": 30,
"+": 31,
"-": 31,
"*": 32,
"/": 32
};
const op = exp[0].toUpperCase();
if (op === "FUNC") {
return `${exp[1]}(${exp
.slice(2)
.map(e => stringify(e))
.join(", ")})`;
} else if (op === "PARAM") {
if (typeof exp[1] === "string") return exp[1];
else if (Array.isArray(exp[1]) && exp[1][0] === "||")
return exp[1]
.slice(1)
.map(p => {
if (typeof p === "string") return p;
else return `{${stringify(p)}}`;
})
.join("");
else return `{${stringify(exp[1])}}`;
} else if (op === "IS NULL" || op === "IS NOT NULL") {
return `${stringify(exp[1])} ${op}`;
} else if (op in opLevels) {
const parts = exp.slice(1).map((e, i) => {
if (
Array.isArray(e) &&
(opLevels[e[0]] < opLevels[exp[0]] ||
(opLevels[e[0]] < opLevels[exp[0]] && i > 0) ||
(opLevels[exp[0]] >= 20 &&
opLevels[e[0]] >= 20 &&
opLevels[e[0]] < 30))
)
return `(${stringify(e)})`;
else return stringify(e);
});
if (op === "NOT") return `${op} ${parts[0]}`;
else return parts.join(` ${op} `);
} else {
throw new Error(`Unrecognized operator ${exp[0]}`);
}
}
exports.parse = parse;
exports.stringify = stringify;
exports.map = map;