4 releases
0.1.1 | Apr 3, 2023 |
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0.1.1-rc.3 | Apr 1, 2023 |
#2424 in Development tools
42 downloads per month
62KB
1.5K
SLoC
Mogglo
Mogglo is a multi-language AST-based code search and rewriting tool. Mogglo supports embedding Lua code in search patterns and replacements.
Mogglo focuses on the following goals:
- Minimal setup: Mogglo will work right away on any codebase in a supported language.
- Many languages: 12 and counting!
- High-quality grammars: Mogglo is based on tree-sitter grammars.
- Lua: Mogglo exposes a rich API to embedded Lua snippets.
Introduction
The following examples give a taste of Mogglo. Here's how to find pointless assignments of an expression to itself:
mogglo-rust --detail 'let $x = $x;' ./**/*.rs
Lua code is wrapped in braces. Lua can recursively match patterns with rec
.
Here's a pattern to detect out-of-bounds array accesses:
mogglo-rust 'while $i <= $buf.len() { ${{ rec("$buf.get($i)") }} }' ./**/*.rs
Here's how to unroll a simple loop:
mogglo-rust \
'for $i in 0..$h { $b; }' \
--where 'h_num = tonumber(h); return h_num ~= nil and h_num % 4 == 0' \
--replace 'for $i in 0..${{ string.format("%.0f", h / 4) }} { $b; $b; $b; $b; }' \
./*/**.rs
This transformation demonstrates the power of using Lua: it can't be done with regular expression substitutions and would be very difficult with other codemod tools.
See the documentation for more details!
Dependencies
~13MB
~280K SLoC