Matching first line of large code-block

[Abhiram98]

Firstly, thanks for the awesome tool!

I've been trying to use the tool to match python code fragments(~5-10 loc), while allowing multiple random statements in between. I've been trying to use the "preceeds" relational rule, along with a "stopBy:end" condition, but that doesn't seem to be working.

Here is a link to the playground I've been working with.

Here is the code-block I would like to search for

count = 0
for i in array:
    count += i

Here are some code-blocks that I would like to match:

count = 0
<random line(s) of code>
for i in array:
    <random line(s) of code>
    count += i

count = 0
s=1+2
x=1
for i in array:
    y = 124
    count += i

[HerringtonDarkholme]

Sorry I didn't quite get what your error message means. I guess you want to match a variable that is incremented in a for loop?

It it was the case, this playground link should work.

rule:
  pattern: 
    context: $COUNT = $_
    selector: expression_statement
  precedes:
    kind: for_statement
    has:
      pattern: $COUNT += $_
      stopBy: end
    stopBy: end

[Abhiram98]

I would like to search for this entire code block:

count = 0
for i in array:
    count += i

And I would like the search to find matches even if there are some additional statements in between the count=0 and the for loop.

[HerringtonDarkholme]

Nope, this is currently impossible to match multiple nodes using YAML now. You can try napi/python API instead.

[Abhiram98]

I don't mind matching just the first statement count=0. This is kind of what I'm going for, but a comment seems to break the search?

[HerringtonDarkholme]

Python tree-sitter gives different output so the pattern needs to change.

You can also inspect the AST in the playground. playground manual is on the top of page.

[HerringtonDarkholme]

If you really need to report multiple lines without using programmatic API. You can use JSON mode.

id: test
language: python
rule:
  pattern:
    context: $COUNT = $_
    selector: expression_statement
  precedes:
    pattern: $LOOP
    kind: for_statement
    has:
      pattern: $COUNT += $_
      stopBy: end
    stopBy: end

sg scan -r test.yml test.py --json | jq '.[].metaVariables.single'

Which gives you the start line of COUNT and the end line of LOOP

[Abhiram98]

Thanks for your replies, they were helpful! This is what I ended up with

[HerringtonDarkholme]

Nice! Thanks for trying out ast-grep!