ruby - How does module_eval / class_eval / instance_eval counts the line numbers -


i have found line_number passed class_eval, module_eval , instance_eval doesn't match line numbers reported error. behaviour not explained ruby-doc says: (use instance_eval example)

the optional second , third parameters supply filename , starting line number used when reporting compilation errors.

all these 3 methods class_eval, module_eval , instance_eval accepts 2 additional params specify filename , lineno parameters set text error messages.

this question has practical demo behavior.

however, have found calculation of line numbers more complex explanation. here demo

class thing   def add_method     = %{       non_exist     }     instance_eval(a, 'dummy', 12)   end end  # error raise 15 instead of 12 specified  puts thing.new.add_method

the code above proves line_no param passed instance_eval not line numbers reported error related line_no.

i wondering exact behavior of params?

as snippet of documentation states, lineno specifies starting line number of pseudo-file. string eval contains 3 lines, second line contains non_exist (%{} preserves line breaks).

when execute code, error in line 14, not 15 receive. have expected 13, seems ruby parser "notice" error on next line, possibly looking method arguments or else make sense of non_exists (i not sure on that). if insert blank line (that contains no indentation) after non_exists, expected 13.

any lines inserted after %{ before non_exists increment line number in error one, should expected.


Comments

Post a Comment

Popular posts from this blog

SPSS keyboard combination alters encoding -

my question not have programming practical issue on spss. accident keyword combination cannot remember because did not intend press changed encoding in spss , text in data in different language english shown small boxes. nevertheless, when kind of analysis performed different language text shown in output. does know reason? tried change encoding did not produce result. first, @ edit > options , see whether setting unicode or locale. might fix it. if have text in multiple languages, want unicode. otherwise, may have specific locale set wrong. can change set locale, need know locale want use.
Read more

Add new record to the table by click on the button in Microsoft Access -

in ms access form want implement separate button, adds new record table. in order added button , attached button event: private sub btnaddrec_click() refresh codecontextobject on error resume next docmd.gotorecord , , acnewrec if err.number <> 0 btnaddrec.enabled = false end if end end sub everything ok when open window , click btnaddrec button, problem when first of perform navigation through existed records , after click on button. got runtime error: 2105: «you can't go specified record. may @ end of recordset» . how solve issue, need have ability add new record on click on specific button, no matter, have walked or not walked through records before. thanks. i created simple form field call description (and autonumber) , created button code follows click event. filled number of records , navigated through them, clicked addnewrec button. form navigated new record without issues. able click addnewrec button directly after ...
Read more

CSS3 Transition to highlight new elements created in JQuery -

i want use css3 color transition apply highlight-fading color effect (yellow transparent) new elements appended markup using jquery. css #content div { background-color:transparent; -moz-transition:background-color 2s; -webkit-transition:background-color 2s; -o-transition:background-color 2s; transition:background-color 2s; } #content div.new { background-color:yellow; } html <div id="content"></div> <a id="add-element" href="#">add new element</a> js $('#add-element').click(function() { var newelement = $('<div class="new">new element</div>'); $('#content').append(newelement); newelement.removeclass('new'); }); when click link, new element created. class "new" (background color yellow) , it's appended html markup. should able remove "new" class trigger background color transition transparent (or whate...
Read more