Report left recursion also in cases where the recursive rule invocation
is not a direct element of a sequence, but is wrapped inside an
expression.
Fixes#359.
Add missing |named| case to the visitor in lib/compiler/asts.js, which
makes the infinite loop and left recursion detectors work correctly with
named rules.
The missing case caused |make parser| to fail with:
140:34: Infinite loop detected.
make: *** [parser] Error 1
Preform the following renames:
* |reportedPos| -> |savedPos| (abstract machine variable)
* |peg$reportedPos| -> |peg$savedPos| (variable in generated code)
* |REPORT_SAVED_POS| -> |LOAD_SAVED_POS| (instruction)
* |REPORT_CURR_POS| -> |UPDATE_SAVED_POS| (instruction)
The idea is that the name |reportedPos| is no longer accurate after the
|location| change (seea the previous commit) because now both
|reportedPos| and |currPos| are reported to user code. Renaming to
|savedPos| resolves this inaccuracy.
There is probably some better name for the concept than quite generic
|savedPos|, but it doesn't come to me.
So far, left recursion detector assumed that left recursion occurs only
when the recursive rule is at the very left-hand side of rule's
expression:
start = start
This didn't catch cases like this:
start = "a"? start
In general, if a rule reference can be reached without consuming any
input, it can lead to left recursion. This commit fixes the detector to
consider that.
Fixes#190.
Unit specs are unit tests of internal stuff. API specs are tests of the
user-visible APIs and behavior.
I think it makes sense to make this distinction because then the public
API line is more clearly visible e.g. when using the specs as
documentation.
David Majda
Arlo Breault