minor tweak to sequence manipulations

- loop through `AST_Seq` chain instead of recursion
- avoid deep-cloning in `lift_sequences()`
- `AST_Seq.car` should never be `null` or `AST_Seq`
- `AST_Seq.cdr` should never be `null`
This commit is contained in:
alexlamsl 2017-02-01 21:33:42 +08:00
parent 7f8d72d9d3
commit 7413899ad4
4 changed files with 77 additions and 68 deletions

View File

@ -589,6 +589,15 @@ var AST_Seq = DEFNODE("Seq", "car cdr", {
cdr: "[AST_Node] second element in sequence"
},
$cons: function(x, y) {
if (!x) {
throw new Error('AST_Seq.car missing');
}
if (!y) {
throw new Error('AST_Seq.cdr missing');
}
if (x instanceof AST_Seq) {
throw new Error('AST_Seq.car cannot be AST_Seq');
}
var seq = new AST_Seq(x);
seq.car = x;
seq.cdr = y;
@ -596,54 +605,48 @@ var AST_Seq = DEFNODE("Seq", "car cdr", {
},
$from_array: function(array) {
if (array.length == 0) return null;
if (array.length == 1) return array[0].clone();
var list = null;
for (var i = array.length; --i >= 0;) {
if (array.length == 1) return array[0];
var i = array.length - 1;
var list = array[i];
while (--i >= 0) {
list = AST_Seq.cons(array[i], list);
}
var p = list;
while (p) {
if (p.cdr && !p.cdr.cdr) {
p.cdr = p.cdr.car;
break;
}
p = p.cdr;
}
return list;
},
to_array: function() {
var p = this, a = [];
while (p) {
var a = [];
var p = this;
do {
a.push(p.car);
if (p.cdr && !(p.cdr instanceof AST_Seq)) {
a.push(p.cdr);
break;
}
p = p.cdr;
}
} while (p instanceof AST_Seq);
a.push(p);
return a;
},
add: function(node) {
tail: function() {
var p = this;
while (p) {
if (!(p.cdr instanceof AST_Seq)) {
var cell = AST_Seq.cons(p.cdr, node);
return p.cdr = cell;
}
while (p.cdr instanceof AST_Seq) {
p = p.cdr;
}
return p;
},
add: function(node) {
var p = this.tail();
p.cdr = AST_Seq.cons(p.cdr, node);
},
len: function() {
if (this.cdr instanceof AST_Seq) {
return this.cdr.len() + 1;
} else {
return 2;
var i = 2;
var p = this.cdr;
while (p instanceof AST_Seq) {
p = p.cdr;
i++;
}
return i;
},
_walk: function(visitor) {
return visitor._visit(this, function(){
this.car._walk(visitor);
if (this.cdr) this.cdr._walk(visitor);
this.cdr._walk(visitor);
});
}
});

View File

@ -938,7 +938,7 @@ merge(Compressor.prototype, {
return this.operator == "=" && this.right.is_boolean();
});
def(AST_Seq, function(){
return this.cdr.is_boolean();
return this.tail().cdr.is_boolean();
});
def(AST_True, return_true);
def(AST_False, return_true);
@ -961,7 +961,7 @@ merge(Compressor.prototype, {
return (this.operator == "=" || this.operator == "+=") && this.right.is_string(compressor);
});
def(AST_Seq, function(compressor){
return this.cdr.is_string(compressor);
return this.tail().cdr.is_string(compressor);
});
def(AST_Conditional, function(compressor){
return this.consequent.is_string(compressor) && this.alternative.is_string(compressor);
@ -1340,8 +1340,12 @@ merge(Compressor.prototype, {
return !compressor.option("pure_getters");
});
def(AST_Seq, function(compressor){
return this.car.has_side_effects(compressor)
|| this.cdr.has_side_effects(compressor);
var p = this;
do {
if (p.car.has_side_effects(compressor)) return true;
p = p.cdr;
} while (p instanceof AST_Seq);
return p.has_side_effects(compressor);
});
})(function(node, func){
node.DEFMETHOD("has_side_effects", func);
@ -2353,12 +2357,11 @@ merge(Compressor.prototype, {
AST_Unary.DEFMETHOD("lift_sequences", function(compressor){
if (compressor.option("sequences")) {
if (this.expression instanceof AST_Seq) {
var seq = this.expression;
var x = seq.to_array();
this.expression = x.pop();
x.push(this);
seq = AST_Seq.from_array(x).transform(compressor);
var seq = this.expression;
if (seq instanceof AST_Seq) {
var p = seq.tail();
this.expression = p.cdr;
p.cdr = this.transform(compressor);
return seq;
}
}
@ -2371,8 +2374,9 @@ merge(Compressor.prototype, {
OPT(AST_UnaryPrefix, function(self, compressor){
self = self.lift_sequences(compressor);
var e = self.expression;
if (!(self instanceof AST_UnaryPrefix)) return self;
if (compressor.option("booleans") && compressor.in_boolean_context()) {
var e = self.expression;
switch (self.operator) {
case "!":
if (e instanceof AST_UnaryPrefix && e.operator == "!") {
@ -2409,22 +2413,20 @@ merge(Compressor.prototype, {
AST_Binary.DEFMETHOD("lift_sequences", function(compressor){
if (compressor.option("sequences")) {
if (this.left instanceof AST_Seq) {
var seq = this.left;
var x = seq.to_array();
this.left = x.pop();
x.push(this);
seq = AST_Seq.from_array(x).transform(compressor);
var seq = this.left;
if (seq instanceof AST_Seq) {
var p = seq.tail();
this.left = p.cdr;
p.cdr = this.transform(compressor);
return seq;
}
if (this.right instanceof AST_Seq
seq = this.right;
if (seq instanceof AST_Seq
&& this instanceof AST_Assign
&& !has_side_effects_or_prop_access(this.left, compressor)) {
var seq = this.right;
var x = seq.to_array();
this.right = x.pop();
x.push(this);
seq = AST_Seq.from_array(x).transform(compressor);
var p = seq.tail();
this.right = p.cdr;
p.cdr = this.transform(compressor);
return seq;
}
}
@ -2492,6 +2494,7 @@ merge(Compressor.prototype, {
}
}
self = self.lift_sequences(compressor);
if (!(self instanceof AST_Binary)) return self;
if (compressor.option("comparisons")) switch (self.operator) {
case "===":
case "!==":
@ -2735,6 +2738,7 @@ merge(Compressor.prototype, {
var ASSIGN_OPS_COMMUTATIVE = [ '*', '|', '^', '&' ];
OPT(AST_Assign, function(self, compressor){
self = self.lift_sequences(compressor);
if (!(self instanceof AST_Assign)) return self;
if (self.operator == "=" && self.left instanceof AST_SymbolRef && self.right instanceof AST_Binary) {
// x = expr1 OP expr2
if (self.right.left instanceof AST_SymbolRef
@ -2757,12 +2761,16 @@ merge(Compressor.prototype, {
});
OPT(AST_Conditional, function(self, compressor){
if (!compressor.option("conditionals")) return self;
if (self.condition instanceof AST_Seq) {
var car = self.condition.car;
self.condition = self.condition.cdr;
return AST_Seq.cons(car, self);
if (compressor.option("sequences")) {
var seq = self.condition;
if (seq instanceof AST_Seq) {
var p = seq.tail();
self.condition = p.cdr;
p.cdr = self.transform(compressor);
return seq;
}
}
if (!compressor.option("conditionals")) return self;
var cond = self.condition.evaluate(compressor);
if (cond.length > 1) {
if (cond[1]) {
@ -2844,7 +2852,7 @@ merge(Compressor.prototype, {
&& consequent.equivalent_to(alternative)) {
var consequent_value = consequent.evaluate(compressor)[0];
if (self.condition.has_side_effects(compressor)) {
return AST_Seq.from_array([self.condition, consequent_value]);
return AST_Seq.cons(self.condition, consequent_value);
} else {
return consequent_value;
}

View File

@ -1082,14 +1082,12 @@ function OutputStream(options) {
AST_Seq.DEFMETHOD("_do_print", function(output){
this.car.print(output);
if (this.cdr) {
output.comma();
if (output.should_break()) {
output.newline();
output.indent();
}
this.cdr.print(output);
output.comma();
if (output.should_break()) {
output.newline();
output.indent();
}
this.cdr.print(output);
});
DEFPRINT(AST_Seq, function(self, output){
self._do_print(output);

View File

@ -29,6 +29,7 @@ typeof_in_boolean_context: {
booleans : true,
evaluate : true,
conditionals : true,
sequences : true,
};
input: {
function f1(x) { return typeof x ? "yes" : "no"; }
@ -40,8 +41,7 @@ typeof_in_boolean_context: {
expect: {
function f1(x) { return "yes"; }
function f2() { return g(), "Yes"; }
foo();
!(console.log(1), !0);
var a = !(console.log(2), !0);
foo(), console.log(1), !1;
var a = (console.log(2), !1);
}
}