summaryrefslogtreecommitdiffstats
path: root/js/src/tests/js1_8_5/reflect-parse/Match.js
blob: 0d5b35317ce046c71d6d8c1e4745316dc3680654 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
// |reftest| skip

// A little pattern-matching library.
var Match =

(function() {

    function Pattern(template) {
        // act like a constructor even as a function
        if (!(this instanceof Pattern))
            return new Pattern(template);

        this.template = template;
    }

    Pattern.prototype = {
        match: function(act) {
            return match(act, this.template);
        },

        matches: function(act) {
            try {
                return this.match(act);
            }
            catch (e if e instanceof MatchError) {
                return false;
            }
        },

        assert: function(act, message) {
            try {
                return this.match(act);
            }
            catch (e if e instanceof MatchError) {
                throw new Error((message || "failed match") + ": " + e.message);
            }
        },

        toString: () => "[object Pattern]"
    };

    Pattern.ANY = new Pattern;
    Pattern.ANY.template = Pattern.ANY;

    Pattern.NUMBER = new Pattern;
    Pattern.NUMBER.match = function (act) {
      if (typeof act !== 'number') {
        throw new MatchError("Expected number, got: " + quote(act));
      }
    }

    Pattern.NATURAL = new Pattern
    Pattern.NATURAL.match = function (act) {
      if (typeof act !== 'number' || act !== Math.floor(act) || act < 0) {
        throw new MatchError("Expected natural number, got: " + quote(act));
      }
    }

    var quote = uneval;

    function MatchError(msg) {
        this.message = msg;
    }

    MatchError.prototype = {
        toString: function() {
            return "match error: " + this.message;
        }
    };

    function isAtom(x) {
        return (typeof x === "number") ||
            (typeof x === "string") ||
            (typeof x === "boolean") ||
            (x === null) ||
            (typeof x === "object" && x instanceof RegExp);
    }

    function isObject(x) {
        return (x !== null) && (typeof x === "object");
    }

    function isFunction(x) {
        return typeof x === "function";
    }

    function isArrayLike(x) {
        return isObject(x) && ("length" in x);
    }

    function matchAtom(act, exp) {
        if ((typeof exp) === "number" && isNaN(exp)) {
            if ((typeof act) !== "number" || !isNaN(act))
                throw new MatchError("expected NaN, got: " + quote(act));
            return true;
        }

        if (exp === null) {
            if (act !== null)
                throw new MatchError("expected null, got: " + quote(act));
            return true;
        }

        if (exp instanceof RegExp) {
            if (!(act instanceof RegExp) || exp.source !== act.source)
                throw new MatchError("expected " + quote(exp) + ", got: " + quote(act));
            return true;
        }

        switch (typeof exp) {
        case "string":
            if (act !== exp)
                throw new MatchError("expected " + quote(exp) + ", got " + quote(act));
            return true;
        case "boolean":
        case "number":
            if (exp !== act)
                throw new MatchError("expected " + exp + ", got " + quote(act));
            return true;
        }

        throw new Error("bad pattern: " + exp.toSource());
    }

    function matchObject(act, exp) {
        if (!isObject(act))
            throw new MatchError("expected object, got " + quote(act));

        for (var key in exp) {
            if (!(key in act))
                throw new MatchError("expected property " + quote(key) + " not found in " + quote(act));
            match(act[key], exp[key]);
        }

        return true;
    }

    function matchFunction(act, exp) {
        if (!isFunction(act))
            throw new MatchError("expected function, got " + quote(act));

        if (act !== exp)
            throw new MatchError("expected function: " + exp +
                                 "\nbut got different function: " + act);
    }

    function matchArray(act, exp) {
        if (!isObject(act) || !("length" in act))
            throw new MatchError("expected array-like object, got " + quote(act));

        var length = exp.length;
        if (act.length !== exp.length)
            throw new MatchError("expected array-like object of length " + length + ", got " + quote(act));

        for (var i = 0; i < length; i++) {
            if (i in exp) {
                if (!(i in act))
                    throw new MatchError("expected array property " + i + " not found in " + quote(act));
                match(act[i], exp[i]);
            }
        }

        return true;
    }

    function match(act, exp) {
        if (exp === Pattern.ANY)
            return true;

        if (exp instanceof Pattern)
            return exp.match(act);

        if (isAtom(exp))
            return matchAtom(act, exp);

        if (isArrayLike(exp))
            return matchArray(act, exp);

        if (isFunction(exp))
            return matchFunction(act, exp);

        return matchObject(act, exp);
    }

    return { Pattern: Pattern,
             MatchError: MatchError };

})();