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lpeg 1.0.1

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Cloud Wu
2017-04-11 13:09:24 +08:00
parent 6fa241453c
commit 8e7796a672
12 changed files with 253 additions and 118 deletions
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3rd/lpeg/lpeg.html
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@@ -10,7 +10,7 @@
</head>
<body>
<!-- $Id: lpeg.html,v 1.75 2015/09/28 17:17:41 roberto Exp $ -->
<!-- $Id: lpeg.html,v 1.77 2017/01/13 13:40:05 roberto Exp $ -->
<div id="container">
@@ -577,8 +577,9 @@ It is equivalent to the following grammar in standard PEG notation:
<h2><a name="captures">Captures</a></h2>
<p>
A <em>capture</em> is a pattern that creates values
(the so called <em>semantic information</em>) when it matches.
A <em>capture</em> is a pattern that produces values
(the so called <em>semantic information</em>)
according to what it matches.
LPeg offers several kinds of captures,
which produces values based on matches and combine these values to
produce new values.
@@ -632,10 +633,7 @@ or no value when <code>number</code> is zero.</td></tr>
</tbody></table>
<p>
A capture pattern produces its values every time it succeeds.
For instance,
a capture inside a loop produces as many values as matched by the loop.
A capture produces a value only when it succeeds.
A capture pattern produces its values only when it succeeds.
For instance,
the pattern <code>lpeg.C(lpeg.P"a"^-1)</code>
produces the empty string when there is no <code>"a"</code>
@@ -643,14 +641,20 @@ produces the empty string when there is no <code>"a"</code>
while the pattern <code>lpeg.C("a")^-1</code>
does not produce any value when there is no <code>"a"</code>
(because the pattern <code>"a"</code> fails).
A pattern inside a loop or inside a recursive structure
produces values for each match.
</p>
<p>
Usually,
LPeg evaluates all captures only after (and if) the entire match succeeds.
During <em>match time</em> it only gathers enough information
to produce the capture values later.
As a particularly important consequence,
LPeg does not specify when (and if) it evaluates its captures.
(As an example,
consider the pattern <code>lpeg.P"a" / func / 0</code>.
Because the "division" by 0 instructs LPeg to throw away the
results from the pattern,
LPeg may or may not call <code>func</code>.)
Therefore, captures should avoid side effects.
Moreover,
most captures cannot affect the way a pattern matches a subject.
The only exception to this rule is the
so-called <a href="#matchtime"><em>match-time capture</em></a>.
@@ -700,6 +704,12 @@ An <em>Outermost</em> capture means that the capture is not inside
another complete capture.
</p>
<p>
In the same way that LPeg does not specify when it evaluates captures,
it does not specify whether it reuses
values previously produced by the group
or re-evaluates them.
</p>
<h3><a name="cap-cc"></a><code>lpeg.Cc ([value, ...])</code></h3>
<p>
@@ -806,7 +816,7 @@ all replacements.
<h3><a name="cap-t"></a><code>lpeg.Ct (patt)</code></h3>
<p>
Creates a <em>table capture</em>.
This capture creates a table and puts all values from all anonymous captures
This capture returns a table with all values from all anonymous captures
made by <code>patt</code> inside this table in successive integer keys,
starting at 1.
Moreover,
@@ -872,7 +882,8 @@ there is no captured value.
<p>
Creates a <em>match-time capture</em>.
Unlike all other captures,
this one is evaluated immediately when a match occurs.
this one is evaluated immediately when a match occurs
(even if it is part of a larger pattern that fails later).
It forces the immediate evaluation of all its nested captures
and then calls <code>function</code>.
</p>
@@ -1380,13 +1391,13 @@ and the new term for each repetition.
<h2><a name="download"></a>Download</h2>
<p>LPeg
<a href="http://www.inf.puc-rio.br/~roberto/lpeg/lpeg-1.0.0.tar.gz">source code</a>.</p>
<a href="http://www.inf.puc-rio.br/~roberto/lpeg/lpeg-1.0.1.tar.gz">source code</a>.</p>
<h2><a name="license">License</a></h2>
<p>
Copyright &copy; 2007-2015 Lua.org, PUC-Rio.
Copyright &copy; 2007-2017 Lua.org, PUC-Rio.
</p>
<p>
Permission is hereby granted, free of charge,
@@ -1424,7 +1435,7 @@ THE SOFTWARE.
<div id="about">
<p><small>
$Id: lpeg.html,v 1.75 2015/09/28 17:17:41 roberto Exp $
$Id: lpeg.html,v 1.77 2017/01/13 13:40:05 roberto Exp $
</small></p>
</div> <!-- id="about" -->