Support value expressions in filter

This commit is contained in:
Zaid Abdulla committed 2018-12-26 00:20:47 -08:00
1 parent 0e6f08b68b
commit ea2e3707e3
7 files changed
+378 -212

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{
"env": {
"node": true,
"browser": true
},
"parserOptions": {
"ecmaVersion": 8
}
}
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"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 binaryLeft(operatorsParser, nextParser) {
return parsimmon.seqMap(
nextParser,
parsimmon.seq(operatorsParser, nextParser).many(),
(first, rest) =>
rest.reduce((acc, ch) => {
let [op, another] = ch;
if (op === acc[0]) return acc.concat([another]);
if (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")
)
.skip(parsimmon.optWhitespace);
},
NotOperator: function() {
return parsimmon
.regexp(/not/i)
.result("NOT")
.skip(parsimmon.optWhitespace)
.desc("NOT");
},
AndOperator: function() {
return parsimmon
.regexp(/and/i)
.result("AND")
.skip(parsimmon.optWhitespace)
.desc("AND");
},
OrOperator: function() {
return parsimmon
.regexp(/or/i)
.result("OR")
.skip(parsimmon.optWhitespace)
.desc("OR");
},
Parameter: function(r) {
return parsimmon
.alt(
parsimmon.regexp(/[a-zA-Z0-9_.*]+/),
r.ValueExpression.wrap(
parsimmon.string("{").skip(parsimmon.optWhitespace),
parsimmon.string("}")
)
)
.atLeast(1)
.map(x => (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");
},
FuncValue: function(r) {
return parsimmon.seqMap(
parsimmon
.regexp(/([a-zA-Z0-0_]+)/, 1)
.skip(parsimmon.optWhitespace)
.desc("function"),
r.Value.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.NumberValue,
r.StringValueSql,
r.StringValueJs,
r.FuncValue
);
},
ValueExpression: function(r) {
return binaryLeft(
parsimmon.string("||"),
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.ValueExpression.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.Parameter,
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.Expression.wrap(
parsimmon.string("("),
parsimmon.string(")").skip(parsimmon.optWhitespace)
)
)
)
)
).trim(parsimmon.optWhitespace);
}
});
function parse(filter) {
return lang.Expression.tryParse(filter);
}
function parseExpression(exp) {
return lang.ValueExpression.tryParse(exp);
}
function parseParameter(p) {
return lang.Parameter.tryParse(p);
}
function stringify(filter) {
function value(v) {
if (Array.isArray(v))
if (v[0].toUpperCase() === "FUNC") {
return `${v[1]}(${v
.slice(2)
.map(e => value(e))
.join(", ")})`;
} else {
return v
.slice(1)
.map(e => value(e))
.join(` ${v[0]} `);
}
return JSON.stringify(v);
}
function expressions(v) {
return v.map(e => {
let str = stringify(e);
if (e[0] === "AND" || e[0] === "OR") return `(${str})`;
else return str;
});
}
function parameter(v) {
if (Array.isArray(v) && v[0] === "||")
return v
.slice(1)
.map(x => {
if (Array.isArray(x)) return `{${value(x)}}`;
else return x;
})
.join("");
return v;
}
const op = filter[0].toUpperCase();
if (["AND", "OR"].includes(op))
return expressions(filter.slice(1)).join(` ${op} `);
else if (op === "NOT") return `NOT ${expressions(filter.slice(1))[0]}`;
else if ([">=", "<>", "<=", "=", ">", "<"].includes(op))
return `${parameter(filter[1])} ${op} ${value(filter[2])}`;
else if (["IS NULL", "IS NOT NULL"].includes(op))
return `${parameter(filter[1])} ${op}`;
else throw new Error("Unrecognized operator");
}
function map(filter, callback) {
let clone;
for (let i = 1; i < filter.length; ++i)
if (Array.isArray(filter[i])) {
let sub = map(filter[i], callback);
if (sub != null && sub !== filter[i]) {
clone = clone || filter.slice();
clone[i] = sub;
}
}
return callback(clone || filter) || clone || filter;
}
function and(filter1, filter2) {
if (!filter1) return filter2;
else if (!filter2) return filter1;
let res = ["AND"];
if (filter1[0] === "AND") res = res.concat(filter1.slice(1));
else res.push(filter1);
if (filter2[0] === "AND") res = res.concat(filter2.slice(1));
else res.push(filter2);
return res;
}
function evaluateExpressions(filter, now = Date.now()) {
return map(filter, exp => {
if (exp[0] === "FUNC" && exp[1] === "NOW") {
return now;
} else if (exp[0] === "*") {
let v = exp[1];
for (let i = 2; i < exp.length; ++i) v *= exp[i];
return v;
} else if (exp[0] === "/") {
let v = exp[1];
for (let i = 2; i < exp.length; ++i) v /= exp[i];
return v;
} else if (exp[0] === "+") {
let v = exp[1];
for (let i = 2; i < exp.length; ++i) v += exp[i];
return v;
} else if (exp[0] === "-") {
let v = exp[1];
for (let i = 2; i < exp.length; ++i) v -= exp[i];
return v;
} else if (exp[0] === "||") {
return exp.slice(1).join("");
}
});
}
exports.parse = parse;
exports.parseExpression = parseExpression;
exports.parseParameter = parseParameter;
exports.stringify = stringify;
exports.map = map;
exports.and = and;
exports.evaluateExpressions = evaluateExpressions;