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Lexing does not necessarily use regular expressions. Infact that's a rather messed up way of doing it.

parseable vs parsable[edit]

It seemed to me that the word should be spelled "parsable" following the pattern of elapse/elapsable and traverse/traversable. However, unlike those words a Google search shows fairly even balance between parseable (338,000 hits) and parsable (281,000 hits). Can anyone explain why this word would be treated specially by English speakers? Is it because parse only has one syllable, i.e. so few letters are left after dropping the "e" that people are worried it might be confused with some other root?

I did extensive research into the correct spelling of this word. I found "parsable" (and not "parseable") in the OED and in the unabridged Random House Dictionary of the English Language. The British National Corpus and the Corpus of Contemporary American English between them have three instances of "parsable" and no instances of any other spelling. When I checked it in April 2008, Google gave a hit count of 172,000 for "parsable", 101,000 for "parseable", and 2,120 for "parsible"; however, you can't rely on Google for this kind of inquiry, because it often uses variant spellings as matches. A lot of the Ghits for "parseable" may actually contain the spelling "parsable".
Look at it from another angle: consistency. I searched a machine-readable dictionary of over 100,000 words. In it, I found that the ending -eable occurs in 78 words. Of those, 40 end in -ceable or -geable; the silent -e is retained so that the preceding c or g will be pronounced soft. In 11 more, the e is sounded, as in "agreeable" and "malleable". All of the remaining 27 end in the pattern <long vowel><consonant>eable. Not one of them has a short vowel or two consonants before the ending, as "parseable" would if it were a word. What's more, all 27 of them are variant spellings for words that don't have the silent -e, as in "movable", "moveable". If English spelling were consistent, there would be no doubt that "parsable" is the correct spelling. Therefore, people who spell it "parseable" are just less diligent than I was. But you can't expect everyone to do three or four hours of research before spelling a new word. Gwil (talk) 20:37, 13 June 2012 (UTC)


I came here looking for an explanation of push- and pull- parsing. If anybody would like to contribute such a section or page, I for one would appreciate it. Thanks.

I wouldn't call myself an expert, so I won't put this into the page, but IIRC 'push' and 'pull' parsers relate more to the nature of the API they use to interface to the program. You can 'push' tokens into it and the parser triggers callbacks, or the parser just runs on the entire text and you 'pull' out parsed events.

I really need help - any hope of having this explained in words of one syllable! —Preceding unsigned comment added by Daisymaeholly (talkcontribs) 15:16, 29 May 2008 (UTC)

Parsing in regards to human language?[edit]

I know that nowadays everybody talks about parsing in regards to computer languages, but there really ought to be something in there about ordinary parsing of ordinary languages. Or do you young kids not talk about that stuff anymore? 07:25, 20 November 2006 (UTC)

Yes, what does this mean:
1. Analyze the following and parse words in italics
I cannot tell if to depart in silence,
Or bitterly to speak in your reproof,
Best fitteth my degree or your condition.

--Slashme (talk) 12:10, 19 May 2008 (UTC)

The article appears to be entirely the wrong way round. Parsing is originally a term from grammar and later came to be applied to the analysis of computer languages. It needs to be reworked in order to make this more apparent, as well as including more material about the development of parsing techniques. I have started to do so. GDBarry (talk) 10:26, 24 November 2012 (UTC)

Appropriateness of UCalc link[edit]

The link to UCalc's commercial maths parsing software for Windows seems a little inappropriate here for two reasons. Firstly it is a mathematics parser whereas the article is on parsing in general, and secondly there are numerous platform-independent freeware alternatives such as - which might be more suitable if a link to a mathematics parser is indeed appropriate here. Any thoughts? Chrisjohnson 22:22, 10 March 2007 (UTC)

Parsing Picture[edit]

I'll create a new version of header picture and upload it. Sorry I undid your changes Nikolasmorton. Cheers - DevinCook (talk) 19:31, 25 November 2007 (UTC)

The new picture I created is different from the original. No possible copyright claim can be made given that is it is a general abstraction. We will able to use the new picture. I appreciate your desire to keep this article clean and accurate.

For thehe picture at the bottom of the page, I also created that. I actually uploaded an image I created for my parsing generator, but thought it could help here too. - DevinCook (talk) 20:27, 27 November 2007 (UTC).

Broken Link[edit]

The external link to an Objective C parser is broken. (talk) 12:36, 18 June 2010 (UTC)

Parsing vs parser[edit]

Should the article on "parser" be separated from the one on "parsing"? It was drawn to my attention that this article is mainly focused on the parsing of computer languages and the design of software to do so. It has relatively little to say about (1) the traditional concept of "parsing" (or "clause analysis"), as an educational tool in the teaching of language; (2) the psycholinguistic concept of "parsing" as part of the interpretation of sentences. It has slightly more to say about the development of parsing algorithms in computational linguistics, but that material could also be expanded substantially, as the methods required are different in some respects from those required for the parsing of computer languages.

It strikes me that there's an attempt to talk about too many subjects under one heading. Certainly I think there should be a separate article on parser design from the one on parsing in general. Alternatively might there be separate articles on grammatical parsing (whether by hand or computer) and the parsing of computer languages? GDBarry (talk) 13:45, 24 November 2012 (UTC)

It is a much more well-rounded article now. Thanks for working on it! Libcub (talk) 01:11, 16 January 2013 (UTC)

natural language vs computer language[edit]

Computer language parsing is historically tied to natural language parsing. The


"A parser is a software component that takes input data (frequently text) and builds a data structure"

Some early parsers produced code directly as they were parsing. Code can be considered an instruction list structure. But usually "data structure" brings to mind a more complex structure. Although it is true of today's parsers. BNF, Backus–Naur Form for example is considered computer technology. See the history of the Backus–Naur Form artical.

--Steamerandy (talk) 19:03, 4 October 2014 (UTC) --Steamerandy (talk) 19:03, 4 October 2014 (UTC)

I noticed the example:

print (y)

in regards to context free grammar ...

It seams vague as to how it relates.

It could be a valid sequence. The example seams to be addressing a variable defined before use.

Such a sequence may be valid. It may be a error only if y was not the intended output. What could be said of:

print (y)

Could the same be clamed of the above? Steamerandy (talk) 22:16, 20 October 2016 (UTC)

Is parsing related to chunking?[edit]

... just asking ....

T (talk) 10:39, 9 May 2015 (UTC)

Split proposed[edit]

Natural language parsing and computer language parsing are two related but distinct topics. Both can be expanded further, for example error recovery is not covered here for computer language parsing yet.

I'm going to sit for a couple weeks on this proposal, and if there's no objections I'll move the content. If someone feels that computer language parsing should get more specific title, same as natural language parsing, that can be done at the same time or afterwards, but I don't think it's necessary. Aasasd (talk) 19:26, 3 December 2016 (UTC)