# Patterns for error messages **URL:** \ **Category:** Ruby\ **Created:** [March 1, 2008, 11:41pm UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694 "2008-03-01T23:41:13Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 1, 2008, 11:41pm UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/1 "2008-03-01T23:41:13Z")
Hello all. It seems that the question relates to interpreter “internals”, but I’m afraid of ask silly questions in ruby-core. The question is: why error messages of interpreter has inconsistent addressing system of file and line? There are at many slightly different schemes (and all of them can be present in the same error backtrace): path/file.rb:10: error text path/file.rb:1:in `require': other-path/other-file.rb:31: error text path/file.rb:7:in`method’ error text ^ from path/file.rb:12 And so on. I can’t invent one regexp for my output-capturing text editor (EditPlus on Windows) for catch all cases and automatically extract file and path for navigate me to this path. Thanks for the answers. v. ---
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 2, 2008, 8:37am UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/2 "2008-03-02T08:37:41Z")
Alle Saturday 01 March 2008, Victor ‘Zverok’ Shepelev ha scritto: > v. I can’t find the differences. If you want a regexp which gives the name of the file, I think you can simply use something like: /^.\*(?=:\d+:)/ Stefano ---
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 3, 2008, 12:08am UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/3 "2008-03-03T00:08:43Z")
> > and path for navigate me to this path. For 4 of my cases it would find, respectively: 1. path/file.rb:10: - OK 2. path/file.rb:1: - when I wanted “the real error” address - “other-path/other-file.rb:31:” 3. path/file.rb:7: - OK 4. nothing, because of there’s no last “:” in the string with “^ from”. Even if you delete last “:” from regexp, the result will be unsatisfactory: " ^ from path/file.rb:12" (There would be even more spaces, but you understand the idea) It’s a pain. V. ---
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 3, 2008, 9:43am UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/4 "2008-03-03T09:43:05Z")
Alle Monday 03 March 2008, Victor ‘Zverok’ Shepelev ha scritto: > > > and path for navigate me to this path. > > It’s a pain. > > V. Yes, now I see what you mean. Well, for the second case, it depends on how your editor works exactly. If it has support for regexp groups, you can use the following regexp: /^(?:._:\d+:in\s+`require’:\s+)?(._)(?=:\d+:)/ The name of the file is in the first group (this works also for the first case) Regarding the last case, I think (but I may be wrong) that the third and last one are a single message, split in two lines for some reason. You should try to understand why this happens and act consequently. If you post the full error messages, maybe with a piece of code which generates them, I can try to help you more. Stefano ---
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 3, 2008, 10:23am UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/5 "2008-03-03T10:23:27Z")
From: Stefano C. [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] Sent: Monday, March 03, 2008 10:42 AM > > > > The question is: why error messages of interpreter has inconsistent > > > > And so on. I can’t invent one regexp for my output-capturing text > > > > of > > > > 1. nothing, because of there’s no last “:” in the string with “^ from”. > > your editor works exactly. If it has support for regexp groups, you can use > > the following regexp: > > /^(?:._:\d+:in\s+`require’:\s+)?(._)(?=:\d+:)/ > > The name of the file is in the first group (this works also for the first > case) OK, but this regexp works for the second case ONLY (unfortunately, I have only one “output pattern” setting, so, I am trying to invent the universal one). > Regarding the last case, I think (but I may be wrong) that the third and > last > one are a single message, split in two lines for some reason. You should > try > to understand why this happens and act consequently. If you post the full > error messages, maybe with a piece of code which generates them, I can try > to > help you more. Yes, it is like call stack: first line has something like case1-case3, other lines has something like case4. For ex: D:/!work/home/!stuff/ruby-tricks/test.rb:1:in `require’: ./tricks.rb:31: syntax error, unexpected ‘]’, expecting $end (SyntaxError) p 1,2,3].inject(0){|sum, n| sum + n} ^ from D:/!work/home/!stuff/ruby-tricks/test.rb:1 And I’d be happy to browse all call-stack by clicking on output strings in “Script Output” window of my editor. Most of compilers have “parsing-friendly” output, having the same “file:line: error” strings on each line. Faithfully, I have a proposition to core team for thinking about it. V. ---
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 3, 2008, 10:51am UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/6 "2008-03-03T10:51:18Z")
From: Stefano C. [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] Sent: Monday, March 03, 2008 11:41 AM > > > help you more. > > > ^ from D:/!work/home/!stuff/ruby-tricks/test.rb:1 > > This should take care of all the four patterns: > > /^(?:._:\d+:in\s+`require’:\s+|\s+^\s+from\s+)?(._)(?=:\d+)/ But not this one: “./…/app/models/teachers.rb:7:in `initialize’: undefined local variable” (not saying about that most of regexp engines too dumb for doing ?: and ?= groups). Maybe somebody from core team can comment on the question phrased as: Can the error messages form be more consistend? (Hmmm… Even I’m ready for trying to contribute, I think). Or this kind of questions should be asked in ruby-core? V. ---
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 3, 2008, 11:18am UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/7 "2008-03-03T11:18:39Z")
Alle Monday 03 March 2008, Victor ‘Zverok’ Shepelev ha scritto: > > This should take care of all the four patterns: > > > > /^(?:._:\d+:in\s+`require’:\s+|\s+^\s+from\s+)?(._)(?=:\d+)/ > > But not this one: > > “./…/app/models/teachers.rb:7:in `initialize’: undefined local variable” I think this is a different matter: here, we’re in the first case (the simplest) and the regexp correctly gives: “./…/app/models/teachers.rb” This is the path of the file where the error occurs, relative to the directory where ruby was started. What would you like to get here? > (not saying about that most of regexp engines too dumb for doing ?: and ?= > groups). Are they? I didn’t try many editors (in particular, kate and vim on linux), but they all support them. At any rate, I think you can do without them. If you replace the initial (?: with a simple (, you’ll get the name of the file in the second group instead of the first. The look-ahead at the end can be removed by replacing (._) with [^:]_. which matche any character except the column. This has the side effect of not working with filenames containing ‘:’ (this is the reason I used the look-ahead). Stefano ---
**Author:** ![Victor\_SZverokS\_She](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/46a35a/32.png) [@Victor\_SZverokS\_She](https://www.ruby-forum.com/u/Victor_SZverokS_She)\ **Post date:** [March 3, 2008, 10:43am UTC](https://www.ruby-forum.com/t/patterns-for-error-messages/130694/8 "2008-03-03T10:43:01Z")
Alle Monday 03 March 2008, Victor ‘Zverok’ Shepelev ha scritto: > OK, but this regexp works for the second case ONLY (unfortunately, I have > only one “output pattern” setting, so, I am trying to invent the universal > one). It should work for all the first three cases (at least, it does in ruby, which I’m using to test it). > Yes, it is like call stack: first line has something like case1-case3, other > lines has something like case4. > > For ex: > > D:/!work/home/!stuff/ruby-tricks/test.rb:1:in `require’: ./tricks.rb:31: > syntax error, unexpected ‘]’, expecting $end (SyntaxError) > p 1,2,3].inject(0){|sum, n| sum + n} > ^ from D:/!work/home/!stuff/ruby-tricks/test.rb:1 This should take care of all the four patterns: /^(?:._:\d+:in\s+`require’:\s+|\s+^\s+from\s+)?(._)(?=:\d+)/ Stefano