ref: cdc5bd4585cf5226c2b6a9fe0b08b7fab8461454
parent: 6971398c0518da1507146cc65827b5dbf8e71c01
author: Gregory Pakosz <gregory.pakosz@gmail.com>
date: Mon Dec 23 06:06:25 CST 2013
imported peg-0.1.14
--- /dev/null
+++ b/ChangeLog
@@ -1,0 +1,85 @@
+2013-12-01 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * src/version.h: 0.1.14
+
+ * src/peg.1: Fix several typos and escape backslashes (thanks to
+ Giulio Paci).
+
+ * LICENSE.txt: Replace "the the" with "the".
+
+2013-08-16 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * src/compile.c: Predicate actions can refer to yytext (thanks to
+ Gregory Pakosz).
+
+ * src/leg.leg: Hexadecimal character escapes are supported by leg
+ (thanks to Hugo Etchegoyen).
+
+2013-07-20 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * src/getopt.c: Use BSD-licensed getopt() in Windows
+ build.
+
+ * src/compile.c: Verbose mode handles Variable nodes.
+
+2013-06-03 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * src/leg.leg, src/compile.c: Add error actions via "~" operator.
+
+ * src/compile.c: Support declaration of local variables at the top
+ level of semantic actions. Dynamically grow data structures to
+ remove artificial limits on rule recursion (thanks to Alex
+ Klinkhamer). Many small changes to better support C++.
+
+ * src/peg.1: Update manual page to describe new features.
+
+ Add build files for Win32 and MacOS thanks to Fyodor Sheremetyev).
+
+2012-04-29 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * compile.c: Move global state into a structure to facilitate
+ reentrant and thread-safe parsers (thanks to Dmitry Lipovoi).
+
+2012-03-29 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * leg.leg: Allow nested, matched braces within actions.
+
+2011-11-25 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * compile.c: Fix matching of 8-bit chars to allow utf-8 sequences
+ in matching expressions (thanks to Gregory Pakosz).
+
+2011-11-24 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * compile.c: Allow octal escapes in character classes.
+
+2011-11-24 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * Makefile: Remove dwarf sym dirs when cleaning.
+
+ * compile.c: Fix size calculation when resizing text
+ buffers.
+
+ * leg.leg, peg.peg: Backslash can be escaped.
+
+2009-08-26 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * leg.leg: Fix match of a single single quote character.
+
+ * examples/basic.leg: Rename getline -> nextline to avoid C
+ namespace conflict.
+
+2007-09-13 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * leg.leg: Allow matched braces inside leg actions. Handle empty
+ rules. Handle empty grammars.
+
+2007-08-31 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ * compile.c: Grow buffers while (not if) they are too
+ small. Remove dependencies on grammar files. Add more basic
+ examples.
+
+2007-05-15 Ian Piumarta <com -dot- gmail -at- piumarta (backwards)>
+
+ First public release.
--- /dev/null
+++ b/LICENSE.txt
@@ -1,0 +1,14 @@
+Copyright (c) 2007-2013, Ian Piumarta
+All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the 'Software'), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, and/or sell copies of the
+Software, and to permit persons to whom the Software is furnished to do so,
+provided that the above copyright notice(s) and this permission notice appear
+in all copies or substantial portions of the Software. Inclusion of the
+above copyright notice(s) and this permission notice in supporting
+documentation would be appreciated but is not required.
+
+THE SOFTWARE IS PROVIDED 'AS IS'. USE ENTIRELY AT YOUR OWN RISK.
--- a/README.md
+++ b/README.md
@@ -26,6 +26,8 @@
## Version history
+* **0.1.14** ([zip](../../archive/0.1.14.zip), [tar.gz](../../archive/0.1.14.tar.gz)) — 2013-12-01
+Documentation typos fixed (thanks to Giulio Paci).
* **0.1.13** ([zip](../../archive/0.1.13.zip), [tar.gz](../../archive/0.1.13.tar.gz)) — 2013-08-16
Predicate actions can refer to `yytext` (thanks to Grégory Pakosz).
Hexadecimal character escapes are supported by `leg` (thanks to Hugo Etchegoyen).
--- a/src/leg.c
+++ b/src/leg.c
@@ -1,4 +1,4 @@
-/* A recursive-descent parser generated by peg 0.1.13 */
+/* A recursive-descent parser generated by peg 0.1.14 */
#include <stdio.h>
#include <stdlib.h>
--- a/src/peg.1
+++ b/src/peg.1
@@ -13,9 +13,9 @@
.\"
.\" THE SOFTWARE IS PROVIDED 'AS IS'. USE ENTIRELY AT YOUR OWN RISK.
.\"
-.\" Last edited: 2012-05-17 15:38:34 by piumarta on emilia
+.\" Last edited: 2013-09-09 14:58:44 by piumarta on emilia
.\"
-.TH PEG 1 "April 2012" "Version 0.1"
+.TH PEG 1 "September 2013" "Version 0.1"
.SH NAME
peg, leg \- parser generators
.SH SYNOPSIS
@@ -30,7 +30,7 @@
.I peg
and
.I leg
-are tools for generating recursive-descent parsers: programs that
+are tools for generating recursive\-descent parsers: programs that
perform pattern matching on text. They process a Parsing Expression
Grammar (PEG) [Ford 2004] to produce a program that recognises legal
sentences of that grammar.
@@ -69,10 +69,10 @@
the parser consumes input text according to the parsing rules,
starting from the first rule in the grammar.
.IR yyparse ()
-returns non-zero if the input could be parsed according to the
+returns non\-zero if the input could be parsed according to the
grammar; it returns zero if the input could not be parsed.
.PP
-The prefix 'yy' or 'YY' is prepended to all externally-visible symbols
+The prefix 'yy' or 'YY' is prepended to all externally\-visible symbols
in the generated parser. This is intended to reduce the risk of
namespace pollution in client programs. (The choice of 'yy' is
historical; see
@@ -106,7 +106,7 @@
satisfied when the input contains the string "username".
.nf
- start <- "username"
+ start <\- "username"
.fi
(The quotation marks are
@@ -114,7 +114,7 @@
part of the matched text; they serve to indicate a literal string to
be matched.) In other words,
.IR yyparse ()
-in the generated C source will return non-zero only if the next eight
+in the generated C source will return non\-zero only if the next eight
characters read from the input spell the word "username". If the
input contains anything else,
.IR yyparse ()
@@ -127,12 +127,12 @@
character if "username" is not found.
.nf
- start <- "username"
+ start <\- "username"
/ .
.fi
.IR yyparse ()
-now always returns non-zero (except at the very end of the input). To
+now always returns non\-zero (except at the very end of the input). To
do something useful we can add actions to the rules. These actions
are performed after a complete match is found (starting from the first
rule) and are chosen according to the 'path' taken through the grammar
@@ -140,7 +140,7 @@
marker'.)
.nf
- start <- "username" { printf("%s\\n", getlogin()); }+ start <\- "username" { printf("%s\\n", getlogin()); } / < . > { putchar(yytext[0]); }.fi
@@ -162,7 +162,7 @@
running the command
.nf
- peg -o username.c username.peg
+ peg \-o username.c username.peg
.fi
will save the corresponding parser in the file
@@ -187,7 +187,7 @@
A grammar consists of a set of named rules.
.nf
- name <- pattern
+ name <\- pattern
.fi
The
@@ -200,7 +200,7 @@
.TP
.BR \(dq characters \(dq
A character or string enclosed in double quotes is matched literally.
-The ANSI C esacpe sequences are recognised within the
+The ANSI C escape sequences are recognised within the
.IR characters .
.TP
.BR ' characters '
@@ -212,19 +212,19 @@
If the set begins with an uparrow (^) then the set is negated (the
element matches any character
.I not
-in the set). Any pair of characters separated with a dash (-)
+in the set). Any pair of characters separated with a dash (\-)
represents the range of characters from the first to the second,
inclusive. A single alphabetic character or underscore is matched by
the following set.
.nf
- [a-zA-Z_]
+ [a\-zA\-Z_]
.fi
-Similarly, the following matches any single non-digit character.
+Similarly, the following matches any single non\-digit character.
.nf
- [^0-9]
+ [^0\-9]
.fi
.TP
@@ -233,11 +233,11 @@
the end of file, where there is no character to match.
.TP
.BR ( \ pattern\ )
-Parentheses are used for grouping (modifying the precendence of the
+Parentheses are used for grouping (modifying the precedence of the
operators described below).
.TP
.BR { \ action\ }-Curly braces surround actions. The action is arbitray C source code
+Curly braces surround actions. The action is arbitrary C source code
to be executed at the end of matching. Any braces within the action
must be properly nested. Any input text that was matched before the
action and delimited by angle brackets (see below) is made available
@@ -287,7 +287,7 @@
are present on the input, the match succeeds anyway.
.PP
The above elements and suffixes can be converted into predicates (that
-match arbitray input text and subsequently succeed or fail
+match arbitrary input text and subsequently succeed or fail
.I without
consuming that input) with the following prefixes:
.TP
@@ -323,7 +323,7 @@
statement) is evaluated immediately when the parser reaches the
predicate. If the
.I expression
-yields non-zero (true) the 'match' succeeds and the parser continues
+yields non\-zero (true) the 'match' succeeds and the parser continues
with the next element in the pattern. If the
.I expression
yields zero (false) the 'match' fails and the parser backs up to look
@@ -338,7 +338,7 @@
Sequences can be separated into disjoint alternatives by the
alternation operator '/'.
.TP
-.RB sequence-1\ / \ sequence-2\ / \ ...\ / \ sequence-N
+.RB sequence\-1\ / \ sequence\-2\ / \ ...\ / \ sequence\-N
Each sequence is tried in turn until one of them matches, at which
time matching for the overall pattern succeeds. If none of the
sequences matches then the match of the overall pattern fails.
@@ -351,12 +351,12 @@
rules), and various operators (written as prefixes, suffixes,
juxtaposition for sequencing and and infix alternation operator) that
modify how the elements within the pattern are matched. Matches are
-made from left to right, 'descending' into named sub-rules as they are
+made from left to right, 'descending' into named sub\-rules as they are
encountered. If the matching process fails, the parser 'back tracks'
('rewinding' the input appropriately in the process) to find thenearest alternative 'path' through the grammar. In other words the
-parser performs a depth-first, left-to-right search for the first
-successfully-matching path through the rules. If found, the actions
+parser performs a depth\-first, left\-to\-right search for the first
+successfully\-matching path through the rules. If found, the actions
along the successful path are executed (in the order they were
encountered).
.PP
@@ -372,15 +372,15 @@
the above description.
.nf
- Grammar <- Spacing Definition+ EndOfFile
+ Grammar <\- Spacing Definition+ EndOfFile
- Definition <- Identifier LEFTARROW Expression
- Expression <- Sequence ( SLASH Sequence )*
- Sequence <- Prefix*
- Prefix <- AND Action
+ Definition <\- Identifier LEFTARROW Expression
+ Expression <\- Sequence ( SLASH Sequence )*
+ Sequence <\- Prefix*
+ Prefix <\- AND Action
/ ( AND | NOT )? Suffix
- Suffix <- Primary ( QUERY / STAR / PLUS )?
- Primary <- Identifier !LEFTARROW
+ Suffix <\- Primary ( QUERY / STAR / PLUS )?
+ Primary <\- Identifier !LEFTARROW
/ OPEN Expression CLOSE
/ Literal
/ Class
@@ -389,36 +389,36 @@
/ BEGIN
/ END
- Identifier <- < IdentStart IdentCont* > Spacing
- IdentStart <- [a-zA-Z_]
- IdentCont <- IdentStart / [0-9]
- Literal <- ['] < ( !['] Char )* > ['] Spacing
+ Identifier <\- < IdentStart IdentCont* > Spacing
+ IdentStart <\- [a\-zA\-Z_]
+ IdentCont <\- IdentStart / [0\-9]
+ Literal <\- ['] < ( !['] Char )* > ['] Spacing
/ ["] < ( !["] Char )* > ["] Spacing
- Class <- '[' < ( !']' Range )* > ']' Spacing
- Range <- Char '-' Char / Char
- Char <- '\\\\' [abefnrtv'"\\[\\]\\\\]
- / '\\\\' [0-3][0-7][0-7]
- / '\\\\' [0-7][0-7]?
- / '\\\\' '-'
+ Class <\- '[' < ( !']' Range )* > ']' Spacing
+ Range <\- Char '\-' Char / Char
+ Char <\- '\\\\' [abefnrtv'"\\[\\]\\\\]
+ / '\\\\' [0\-3][0\-7][0\-7]
+ / '\\\\' [0\-7][0\-7]?
+ / '\\\\' '\-'
/ !'\\\\' .
- LEFTARROW <- '<-' Spacing
- SLASH <- '/' Spacing
- AND <- '&' Spacing
- NOT <- '!' Spacing
- QUERY <- '?' Spacing
- STAR <- '*' Spacing
- PLUS <- '+' Spacing
- OPEN <- '(' Spacing- CLOSE <- ')' Spacing
- DOT <- '.' Spacing
- Spacing <- ( Space / Comment )*
- Comment <- '#' ( !EndOfLine . )* EndOfLine
- Space <- ' ' / '\\t' / EndOfLine
- EndOfLine <- '\\r\\n' / '\\n' / '\\r'
- EndOfFile <- !.
- Action <- '{' < [^}]* > '}' Spacing- BEGIN <- '<' Spacing
- END <- '>' Spacing
+ LEFTARROW <\- '<\-' Spacing
+ SLASH <\- '/' Spacing
+ AND <\- '&' Spacing
+ NOT <\- '!' Spacing
+ QUERY <\- '?' Spacing
+ STAR <\- '*' Spacing
+ PLUS <\- '+' Spacing
+ OPEN <\- '(' Spacing+ CLOSE <\- ')' Spacing
+ DOT <\- '.' Spacing
+ Spacing <\- ( Space / Comment )*
+ Comment <\- '#' ( !EndOfLine . )* EndOfLine
+ Space <\- ' ' / '\\t' / EndOfLine
+ EndOfLine <\- '\\r\\n' / '\\n' / '\\r'
+ EndOfFile <\- !.
+ Action <\- '{' < [^}]* > '}' Spacing+ BEGIN <\- '<' Spacing
+ END <\- '>' Spacing
.fi
.SH LEG GRAMMARS
@@ -443,19 +443,19 @@
the code that implements the parser itself.
.TP
.IB name\ = \ pattern
-The 'assignment' operator replaces the left arrow operator '<-'.
+The 'assignment' operator replaces the left arrow operator '<\-'.
.TP
-.B rule-name
+.B rule\-name
Hyphens can appear as letters in the names of rules. Each hyphen is
converted into an underscore in the generated C source code. A single
-single hyphen '-' is a legal rule name.
+single hyphen '\-' is a legal rule name.
.nf
- - = [ \\t\\n\\r]*
- number = [0-9]+ -
- name = [a-zA-Z_][a-zA_Z_0-9]* -
- l-paren = '(' -- r-paren = ')' -
+ \- = [ \\t\\n\\r]*
+ number = [0\-9]+ \-
+ name = [a\-zA\-Z_][a\-zA_Z_0\-9]* \-
+ l\-paren = '(' \-+ r\-paren = ')' \-
.fi
This example shows how ignored whitespace can be obvious when reading
@@ -462,7 +462,7 @@
the grammar and yet unobtrusive when placed liberally at the end of
every rule associated with a lexical element.
.TP
-.IB seq-1\ | \ seq-2
+.IB seq\-1\ | \ seq\-2
The alternation operator is vertical bar '|' rather than forward
slash '/'. The
.I peg
@@ -469,17 +469,17 @@
rule
.nf
- name <- sequence-1
- / sequence-2
- / sequence-3
+ name <\- sequence\-1
+ / sequence\-2
+ / sequence\-3
.fi
is therefore written
.nf
- name = sequence-1
- | sequence-2
- | sequence-3
+ name = sequence\-1
+ | sequence\-2
+ | sequence\-3
;
.fi
@@ -501,7 +501,7 @@
.I yyleng
are not available inside these actions, but the pointer variable
.I yy
-is available to give the code access to any user-defined members
+is available to give the code access to any user\-defined members
of the parser state (see "CUSTOMISING THE PARSER" below).
Note also that
.I exp
@@ -530,20 +530,20 @@
the parser implementation code.
.TP
.BI $$\ = \ value
-A sub-rule can return a semantic
+A sub\-rule can return a semantic
.I value
-from an action by assigning it to the pseudo-variable '$$'. All
+from an action by assigning it to the pseudo\-variable '$$'. All
semantic values must have the same type (which defaults to 'int').
This type can be changed by defining YYSTYPE in a declaration section.
.TP
.IB identifier : name
-The semantic value returned (by assigning to '$$') from the sub-rule
+The semantic value returned (by assigning to '$$') from the sub\-rule
.I name
is associated with the
.I identifier
and can be referred to in subsequent actions.
.PP
-The desk calclator example below illustrates the use of '$$' and ':'.
+The desk calculator example below illustrates the use of '$$' and ':'.
.SH LEG EXAMPLE: A DESK CALCULATOR
The extensions in
.I leg
@@ -553,7 +553,7 @@
we show a simple desk calculator supporting the four common arithmetic
operators and named variables. The intermediate results of arithmetic
evaluation will be accumulated on an implicit stack by returning them
-as semantic values from sub-rules.
+as semantic values from sub\-rules.
.nf
%{@@ -562,7 +562,7 @@
int vars[26];
%}
- Stmt = - e:Expr EOL { printf("%d\\n", e); }+ Stmt = \- e:Expr EOL { printf("%d\\n", e); } | ( !EOL . )* EOL { printf("error\\n"); } Expr = i:ID ASSIGN s:Sum { $$ = vars[i] = s; }@@ -570,7 +570,7 @@
Sum = l:Product
( PLUS r:Product { l += r; }- | MINUS r:Product { l -= r; }+ | MINUS r:Product { l \-= r; } )* { $$ = l; }Product = l:Value
@@ -582,17 +582,17 @@
| i:ID !ASSIGN { $$ = vars[i]; } | OPEN i:Expr CLOSE { $$ = i; }- NUMBER = < [0-9]+ > - { $$ = atoi(yytext); }- ID = < [a-z] > - { $$ = yytext[0] - 'a'; }- ASSIGN = '=' -
- PLUS = '+' -
- MINUS = '-' -
- TIMES = '*' -
- DIVIDE = '/' -
- OPEN = '(' -- CLOSE = ')' -
+ NUMBER = < [0\-9]+ > \- { $$ = atoi(yytext); }+ ID = < [a\-z] > \- { $$ = yytext[0] \- 'a'; }+ ASSIGN = '=' \-
+ PLUS = '+' \-
+ MINUS = '\-' \-
+ TIMES = '*' \-
+ DIVIDE = '/' \-
+ OPEN = '(' \-+ CLOSE = ')' \-
- - = [ \\t]*
+ \- = [ \\t]*
EOL = '\\n' | '\\r\\n' | '\\r' | ';'
%%
@@ -612,9 +612,9 @@
above description.
.nf
- grammar = -
+ grammar = \-
( declaration | definition )+
- trailer? end-of-file
+ trailer? end\-of\-file
declaration = '%{' < ( !'%}' . )* > RPERCENT@@ -643,48 +643,48 @@
| BEGIN
| END
- identifier = < [-a-zA-Z_][-a-zA-Z_0-9]* > -
+ identifier = < [\-a\-zA\-Z_][\-a\-zA\-Z_0\-9]* > \-
- literal = ['] < ( !['] char )* > ['] -
- | ["] < ( !["] char )* > ["] -
+ literal = ['] < ( !['] char )* > ['] \-
+ | ["] < ( !["] char )* > ["] \-
- class = '[' < ( !']' range )* > ']' -
+ class = '[' < ( !']' range )* > ']' \-
- range = char '-' char | char
+ range = char '\-' char | char
char = '\\\\' [abefnrtv'"\\[\\]\\\\]
- | '\\\\' [0-3][0-7][0-7]
- | '\\\\' [0-7][0-7]?
+ | '\\\\' [0\-3][0\-7][0\-7]
+ | '\\\\' [0\-7][0\-7]?
| !'\\\\' .
- action = '{' < braces* > '}' -+ action = '{' < braces* > '}' \- braces = '{' braces* '}'| !'}' .
- EQUAL = '=' -
- COLON = ':' -
- SEMICOLON = ';' -
- BAR = '|' -
- AND = '&' -
- NOT = '!' -
- QUERY = '?' -
- STAR = '*' -
- PLUS = '+' -
- OPEN = '(' -- CLOSE = ')' -
- DOT = '.' -
- BEGIN = '<' -
- END = '>' -
- TILDE = '~' -
- RPERCENT = '%}' -
-
- - = ( space | comment )*
- space = ' ' | '\\t' | end-of-line
- comment = '#' ( !end-of-line . )* end-of-line
- end-of-line = '\\r\\n' | '\\n' | '\\r'
- end-of-file = !.
+ EQUAL = '=' \-
+ COLON = ':' \-
+ SEMICOLON = ';' \-
+ BAR = '|' \-
+ AND = '&' \-
+ NOT = '!' \-
+ QUERY = '?' \-
+ STAR = '*' \-
+ PLUS = '+' \-
+ OPEN = '(' \-+ CLOSE = ')' \-
+ DOT = '.' \-
+ BEGIN = '<' \-
+ END = '>' \-
+ TILDE = '~' \-
+ RPERCENT = '%}' \-
+ \- = ( space | comment )*
+ space = ' ' | '\\t' | end\-of\-line
+ comment = '#' ( !end\-of\-line . )* end\-of\-line
+ end\-of\-line = '\\r\\n' | '\\n' | '\\r'
+ end\-of\-file = !.
+
.fi
.SH CUSTOMISING THE PARSER
The following symbols can be redefined in declaration sections to
@@ -691,7 +691,7 @@
modify the generated parser code.
.TP
.B YYSTYPE
-The semantic value type. The pseudo-variable '$$' and the
+The semantic value type. The pseudo\-variable '$$' and the
identifiers 'bound' to rule results with the colon operator ':' should
all be considered as being declared to have this type. The default
value is 'int'.
@@ -788,7 +788,7 @@
If this symbol is defined during compilation of a generated parser
then global parser state will be kept in a structure of
type 'yycontext' which can be declared as a local variable. This
-allows multiple instances of parsers to coexist and to be thread-safe.
+allows multiple instances of parsers to coexist and to be thread\-safe.
The parsing function
.IR yyparse ()
will be declared to expect a first argument of type 'yycontext *', an
@@ -801,7 +801,7 @@
#define YY_CTX_LOCAL
- #include "the-generated-parser.peg.c"
+ #include "the\-generated\-parser.peg.c"
int main()
{@@ -814,13 +814,13 @@
.fi
Note that if this symbol is undefined then the compiled parser will
statically allocate its global state and will be neither reentrant nor
-thread-safe.
+thread\-safe.
Note also that the parser yycontext structure is initialised automatically
the first time
.IR yyparse ()
is called; this structure
.B must
-therefore be properly initliased to zero before the first call to
+therefore be properly initialised to zero before the first call to
.IR yyparse ().
.TP
.B YY_CTX_MEMBERS
@@ -829,7 +829,7 @@
that the client would like included in the declaration of
the 'yycontext' structure type. These additional members are
otherwise ignored by the generated parser. The instance
-of 'yycontext' associated with the currently-active parser is
+of 'yycontext' associated with the currently\-active parser is
available within actions as the pointer variable
.IR yy .
.TP
@@ -847,15 +847,15 @@
this to avoid unnecessary buffer reallocation.
.TP
.BI YY_MALLOC( YY , \ SIZE )
-The memory allocator for all parser-related storage. The parameters
+The memory allocator for all parser\-related storage. The parameters
are the current yycontext structure and the number of bytes to
allocate. The default definition is:
.RI malloc( SIZE )
.TP
.BI YY_REALLOC( YY , \ PTR , \ SIZE )
-The memory reallocator for dynamically-grown storage (such as text
+The memory reallocator for dynamically\-grown storage (such as text
buffers and variable stacks). The parameters are the current
-yycontext structure, the previously-allocated storage, and the number
+yycontext structure, the previously\-allocated storage, and the number
of bytes to which that storage should be grown. The default definition is:
.RI realloc( PTR , \ SIZE )
.TP
@@ -868,7 +868,7 @@
The name of the function that releases all resources held by a
yycontext structure. The default value is 'yyrelease'.
.PP
-The following variables can be reffered to within actions.
+The following variables can be referred to within actions.
.TP
.B char *yybuf
This variable points to the parser's input buffer used to store input
@@ -886,13 +886,13 @@
.TP
.B yycontext *yy
This variable points to the instance of 'yycontext' associated with
-the currently-active parser.
+the currently\-active parser.
.PP
Programs that wish to release all the resources associated with a
parser can use the following function.
.TP
.BI yyrelease(yycontext * yy )
-Returns all parser-allocated storage associated with
+Returns all parser\-allocated storage associated with
.I yy
to the system. The storage will be reallocated on the next call to
.IR yyparse ().
@@ -910,7 +910,7 @@
.I yy
variable passed to actions contains the state of the parser plus any
additional fields defined by YY_CTX_MEMBERS. Theses fields can be
-used to store application-specific information that is global to a
+used to store application\-specific information that is global to a
particular call of
.IR yyparse ().
A trivial but complete
@@ -934,7 +934,7 @@
int count;
%}
- Char = ('\\n' | '\\r\\n' | '\\r') { yy->count++ }+ Char = ('\\n' | '\\r\\n' | '\\r') { yy\->count++ }| .
%%
@@ -994,11 +994,11 @@
.nf
# (6.7.6)
- direct-abstract-declarator =
- LPAREN abstract-declarator RPAREN
- | direct-abstract-declarator? LBRACKET assign-expr? RBRACKET
- | direct-abstract-declarator? LBRACKET STAR RBRACKET
- | direct-abstract-declarator? LPAREN param-type-list? RPAREN
+ direct\-abstract\-declarator =
+ LPAREN abstract\-declarator RPAREN
+ | direct\-abstract\-declarator? LBRACKET assign\-expr? RBRACKET
+ | direct\-abstract\-declarator? LBRACKET STAR RBRACKET
+ | direct\-abstract\-declarator? LPAREN param\-type\-list? RPAREN
.fi
The recursion can easily be eliminated by converting the parts of the
@@ -1006,19 +1006,56 @@
.nf
# (6.7.6)
- direct-abstract-declarator =
- direct-abstract-declarator-head?
- direct-abstract-declarator-tail*
+ direct\-abstract\-declarator =
+ direct\-abstract\-declarator\-head?
+ direct\-abstract\-declarator\-tail*
- direct-abstract-declarator-head =
- LPAREN abstract-declarator RPAREN
+ direct\-abstract\-declarator\-head =
+ LPAREN abstract\-declarator RPAREN
- direct-abstract-declarator-tail =
- LBRACKET assign-expr? RBRACKET
+ direct\-abstract\-declarator\-tail =
+ LBRACKET assign\-expr? RBRACKET
| LBRACKET STAR RBRACKET
- | LPAREN param-type-list? RPAREN
+ | LPAREN param\-type\-list? RPAREN
.fi
+.SH CAVEATS
+A parser that accepts empty input will
+.I always
+succeed. Consider the following example, not atypical of a first
+attempt to write a PEG\-based parser:
+.nf
+
+ Program = Expression*
+ Expression = "whatever"
+ %%
+ int main() {+ while (yyparse())
+ puts("success!");+ return 0;
+ }
+
+.fi
+This program loops forever, no matter what (if any) input is provided
+on stdin. Many fixes are possible, the easiest being to insist that
+the parser always consumes some non\-empty input. Changing the first
+line to
+.nf
+
+ Program = Expression+
+
+.fi
+accomplishes this. If the parser is expected to consume the entire
+input, then explicitly requiring the end\-of\-file is also highly
+recommended:
+.nf
+
+ Program = Expression+ !.
+
+.fi
+This works because the parser will only fail to match ("!" predicate)+any character at all ("." expression) when it attempts to read beyond+the end of the input.
.SH BUGS
You have to type 'man peg' to read the manual page for
.IR leg (1).
@@ -1037,32 +1074,32 @@
.B ~
should really be named the other way around.
.PP
-Several commonly-used
+Several commonly\-used
.IR lex (1)
features (yywrap(), yyin, etc.) are completely absent.
.PP
-The generated parser foes not contain '#line' directives to direct C
+The generated parser does not contain '#line' directives to direct C
compiler errors back to the grammar description when appropriate.
.SH SEE ALSO
D. Val Schorre,
-.I META II, a syntax-oriented compiler writing language,
-19th ACM National Conference, 1964, pp.\ 41.301--41.311. Describes a
-self-implementing parser generator for analytic grammars with no
+.I META II, a syntax\-oriented compiler writing language,
+19th ACM National Conference, 1964, pp.\ 41.301\-\-41.311. Describes a
+self\-implementing parser generator for analytic grammars with no
backtracking.
.PP
Alexander Birman,
.I The TMG Recognition Schema,
Ph.D. dissertation, Princeton, 1970. A mathematical treatment of the
-power and complexity of recursive-descent parsing with backtracking.
+power and complexity of recursive\-descent parsing with backtracking.
.PP
Bryan Ford,
-.I Parsing Expression Grammars: A Recognition-Based Syntactic Foundation,
+.I Parsing Expression Grammars: A Recognition\-Based Syntactic Foundation,
ACM SIGPLAN Symposium on Principles of Programming Languages, 2004.
-Defines PEGs and analyses them in relation to context-free and regular
+Defines PEGs and analyses them in relation to context\-free and regular
grammars. Introduces the syntax adopted in
.IR peg .
.PP
-The standard Unix utilies
+The standard Unix utilities
.IR lex (1)
and
.IR yacc (1)
@@ -1084,9 +1121,9 @@
.SH AUTHOR
.IR peg ,
.I leg
-and this manual page were written by Ian Piumarta (first-name at
-last-name dot com) while investigating the viablility of regular- and
-parsing-expression grammars for efficiently extracting type and
+and this manual page were written by Ian Piumarta (first\-name at
+last\-name dot com) while investigating the viability of regular and
+parsing\-expression grammars for efficiently extracting type and
signature information from C header files.
.PP
Please send bug reports and suggestions for improvements to the author
--- a/src/peg.peg-c
+++ b/src/peg.peg-c
@@ -1,4 +1,4 @@
-/* A recursive-descent parser generated by peg 0.1.13 */
+/* A recursive-descent parser generated by peg 0.1.14 */
#include <stdio.h>
#include <stdlib.h>
--- a/src/version.h
+++ b/src/version.h
@@ -1,3 +1,3 @@
#define PEG_MAJOR 0
#define PEG_MINOR 1
-#define PEG_LEVEL 13
+#define PEG_LEVEL 14