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Chasing after issue with abandoning current computation.

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This commit is contained in:
Danny Yoo 2013-04-16 17:14:13 -06:00
parent 30e62139d6
commit 00908c8435
2 changed files with 37 additions and 19 deletions
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6
whalesong/js-assembler/runtime-src/baselib-frames.js
View File

@ -44,6 +44,9 @@
// tag for supporting delimited continuations. To support abort,
// we also keep the size of the environment, and the handler
// to call if an abort happens.
//
// If handler is null, handler will be a default closure that
// accepts any number of values and returns.
var PromptFrame = function(label, tag, envLength, handler) {
this.label = label;
this.tag = tag; // ContinuationPromptTag
@ -55,6 +58,9 @@
//////////////////////////////////////////////////////////////////////
exports.Frame = Frame;
exports.CallFrame = CallFrame;

48
whalesong/js-assembler/runtime-src/baselib-primitives.js
View File

@ -3145,15 +3145,31 @@
});
// The default prompt handler consumes a thunk and applies it.
var defaultPromptHandler =
makeClosure("default-prompt-handler",
1,
function(M) {
var proc = checkProcedure(M, 'apply', 0);
M.e.pop();
M.p = proc;
M.a = 0;
baselib.functions.rawApply(M);
},
[]);
installPrimitiveClosure(
'abort-current-continuation',
2, //baselib.arity.makeArityAtLeast(1),
baselib.arity.makeArityAtLeast(1),
function(M) {
var promptTag = checkPromptTag(M, 'abort-current-continuation', 0);
var vals = [];
var frame;
var i;
for(i = 1; i < M.a; i++) {
vals.push(M.e[M.e.length-1-i]);
vals.push(M.e[M.e.length - 1 - i]);
}
// First, find the continuation prompt.
@ -3161,26 +3177,22 @@
frame = M.c.pop();
if (frame instanceof PromptFrame) {
break;
} else if (M.c.length === 0) {
raiseContractError(
M,
baselib.format.format("continuation includes no prompt with the given tag", []));
}
}
// Shrink the environment to what was observed when the PromptFrame was installed.
// Shrink the environment to what was observed when the
// PromptFrame was installed, and then set up the call
// to the prompt's abort handler.
M.e.length = frame.envLength;
// Default behavior:
// Re-establish the prompt frame and call the thunk.
// FIXME: generalize to different handlers!
M.e.push(c);
if (isProcedure(vals[0])) {
M.p = vals[0];
M.a = 0;
baselib.functions.rawApply(M);
} else {
raiseArgumentTypeError(M,
'abort-current-continuation',
'thunk',
1,
vals[0]);
M.p = frame.handler || defaultPromptHandler;
M.a = vals.length;
for (i = 0; i < vals.length; i++) {
M.e.push(vals[vals.length - i - 1]);
}
baselib.functions.rawApply(M);
});