How to do variable substitution throughout a file for a variable named 'a' and not erroneously change other labels?

Question

I have a series of javascript .js files where the original scripter used poor variable names such as 'a', 'b', etc.

I need to automate the substitution to more descriptive names, reliably only changing the single character variable name(s) and not erroneously modifying other variables which may include that letter.

I am thinking it could be done in awk with something like:

awk '{gsub(/a/, "new_name")};{print}' script.js

but need more sophistication in the regular expression /a/ so as not to change variable names erroneously.

For those of us who don't speak JS, it might be helpful to include a description of the variable naming rules. For example, if names may only include word characters, then it might be possible to restrict the match using word boundary anchors. — steeldriver, Oct 02 '20 at 14:16
you can use sed or perl as well... I think you are looking for word boundaries.. sed 's/\ba\b/new_name/g' script.js or perl -pe 's/\ba\b/new_name/g' script.js if \b isn't supported by your sed implementation — Sundeep, Oct 02 '20 at 14:51
See also: Replacing pattern only when it matches a whole word — Sundeep, Oct 02 '20 at 14:52
Assuming JS includes the ability to enter text strings, comments, etc, <new_name_for_I> would think some syntactic analysis would be <new_name_for a> very good idea. — Paul_Pedant, Oct 02 '20 at 16:00
In general it's impossible to do this task robustly with a regexp since it can't tell a variable a from a in the middle of a string or a comment or elsewhere. If you have specific code where a only appears in a specific context THEN you might be able to do what you want but we'd need to see that code to be able to help you. — Ed Morton, Oct 02 '20 at 16:35
You have to use some tool written in js and specific for parsing js code. Like this and I am sure you will find more with a good search. These code parsing tools should also validate the code after any change. — thanasisp, Oct 02 '20 at 17:16
Here is a portion of the .js file. I am not a javascript programmer so I cannot comment on the functionality. The "problem" is to perform the variable substitution as I mention above.
(function(){var E;var g=window,n=document,p=function(a){var b=g._gaUserPrefs;if(b&&b.ioo&&b.ioo()||a&&!0===g["ga-disable-"+a])return!0;try{var c=g.external;if(c&&c._gaUserPrefs&&"oo"==c._gaUserPrefs)return!0} — Debra McCusker, Oct 02 '20 at 18:23
Well folks, I believe that I have a solution; at least it is close.

I have created a file named charac-sub.awk with:
{gsub(/\/,"new_name1")}; {print}
{gsub(/\/,"new_name2")}; {print}
. .

and when I run it from the command line:

awk -f charac-sub.awk gs_script.js

It seems to do what I need. — Debra McCusker, Oct 02 '20 at 20:29
Don't post additional information in comments where it can't be formatted and might be missed, [edit] your question to include all relevant information. — Ed Morton, Oct 03 '20 at 20:42

Debra McCusker · Answer 1 · 2020-10-02T21:17:31.910

0

Well folks, I believe that I have a solution; at least it is close.

I have created a file named charac-sub.awk with:
{gsub(/\<a>/,"new_name1")
gsub(/\<b>/,"new_name2")
.
.
gsub(/\<e>/,"new_nameN")}; {print}

and when I run it from the command line:

awk -f charac-sub.awk script.js

It seems to do what I need.

edited Oct 02 '20 at 21:17

answered Oct 02 '20 at 20:34

Debra McCusker

1

How to do variable substitution throughout a file for a variable named 'a' and not erroneously change other labels?

1 Answers1