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Attach context update algorithm to token types

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For, theoretically, easier extendability
This commit is contained in:
Marijn Haverbeke 2015-02-24 10:10:05 +01:00
parent 6bd1013f2c
commit 06f3b3c224
1 changed files with 52 additions and 35 deletions
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87
acorn.js
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@ -281,6 +281,7 @@
this.prefix = kind && kind.indexOf("prefix") > -1;
this.postfix = kind && kind.indexOf("postfix") > -1;
this.binop = binop || null;
this.updateContext = null;
}
@ -392,6 +393,52 @@
kw("void", true, "prefix");
kw("delete", true, "prefix");
// Update tokenizer context for a given token type
tt.parenR.updateContext = tt.braceR.updateContext = function() {
var out = this.context.pop();
if (out === b_stat && this.curTokContext() === f_expr) {
this.context.pop();
this.exprAllowed = false;
} else if (out !== b_tmpl) {
this.exprAllowed = !(out && out.isExpr);
}
};
tt.braceL.updateContext = function(prevType) {
this.context.push(this.braceIsBlock(prevType) ? b_stat : b_expr);
this.exprAllowed = true;
};
tt.dollarBraceL.updateContext = function() {
this.context.push(b_tmpl);
this.exprAllowed = true;
};
tt.parenL.updateContext = function(prevType) {
var statementParens = prevType === tt._if || prevType === tt._for || prevType === tt._with || prevType === tt._while;
this.context.push(statementParens ? p_stat : p_expr);
this.exprAllowed = true;
};
tt.incDec.updateContext = function() {
// tokExprAllowed stays unchanged
};
tt._function.updateContext = function() {
if (this.curTokContext() !== b_stat)
this.context.push(f_expr);
this.exprAllowed = false;
};
tt.backQuote.updateContext = function() {
if (this.curTokContext() === q_tmpl)
this.context.pop();
else
this.context.push(q_tmpl);
this.exprAllowed = false;
};
// This is a trick taken from Esprima. It turns out that, on
// non-Chrome browsers, to check whether a string is in a set, a
// predicate containing a big ugly `switch` statement is faster than
@ -801,43 +848,13 @@
this.type = type;
this.value = val;
// Update context info
if (type === tt.parenR || type === tt.braceR) {
var out = this.context.pop();
if (out === b_stat && this.curTokContext() === f_expr) {
this.context.pop();
this.exprAllowed = false;
} else if (out !== b_tmpl) {
this.exprAllowed = !(out && out.isExpr);
}
} else if (type === tt.braceL) {
this.context.push(this.braceIsBlock(prevType) ? b_stat : b_expr);
this.exprAllowed = true;
} else if (type === tt.dollarBraceL) {
this.context.push(b_tmpl);
this.exprAllowed = true;
} else if (type == tt.parenL) {
var statementParens = prevType === tt._if || prevType === tt._for || prevType === tt._with || prevType === tt._while;
this.context.push(statementParens ? p_stat : p_expr);
this.exprAllowed = true;
} else if (type == tt.incDec) {
// tokExprAllowed stays unchanged
} else if (type.keyword && prevType == tt.dot) {
var update;
if (type.keyword && prevType == tt.dot)
this.exprAllowed = false;
} else if (type == tt._function) {
if (this.curTokContext() !== b_stat) {
this.context.push(f_expr);
}
this.exprAllowed = false;
} else if (type === tt.backQuote) {
if (this.curTokContext() === q_tmpl)
this.context.pop();
else
this.context.push(q_tmpl);
this.exprAllowed = false;
} else {
else if (update = type.updateContext)
update.call(this, prevType);
else
this.exprAllowed = type.beforeExpr;
}
};
// ### Token reading