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Hi, ast-grep author here. This is a great question and I asked this in the first place before I started the hobby project. TLDR; I designed ast-grep to be on d

Hi, ast-grep author here. This is a great question and I asked this in the first place before I started the hobby project. TLDR; I designed ast-grep to be on different tracks than semgrep. Semgrep is for security and ast-grep is for development. First and foremost, I have always been in awe of semgrep. Semgrep's documentation, product sites and Padioleau's podcast all gave me a lot of inspiration. Using code to find code is such a cool idea that I never need to craft an intricate regex or write a lengthy AST program. sgrep and patch from https://github.com/facebookarchive/pfff/wiki/Sgrep https://github.com/facebookarchive/pfff/wiki/Sgrep have helped me a lot in real large codebases. When I used semgrep as a software engineer, instead of a security researcher, I found semgrep has not touched too much on routine development works. I can use `semgrep -e PATTERN` but the Python wrapper is not too fast compared to grep. While pattern is cool, it cannot precisely match some syntax nodes. (example, selecting generator expression in Semgrep is very hard). It also does not have API to find code programmatically. I have also a short summary for tool comparison. https://ast-grep.github.io/advanced/tool-comparison.html https://ast-grep.github.io/advanced/tool-comparison.html

herrington_d 3y ago
Why I think semgrep is a security tool different from ast-grep: * Semgrep is security focused. It has many advanced static analysis features in its core product, such as dataflow analysis, symbolic propagation, and semantic equivalence, all of which are useful for security analysis. They are not available in ast-grep. * Semgrep’s pattern syntax also prefers matching more potentially vulnerable semantics than matching precise syntax. Semantic level information is the better level of abstraction for security model. ast-grep, on the other hand, sticks to faithfully translating users' queries syntactically. * Semgrep has a one-off search and rewrite feature, but it is not its primary focus. The CLI is a bit slow compared to other tools. ast-grep strives to be a fast CLI tool. * Semgrep has a product matrix for vulnerability detection: detecting secrets, supply chain vulnerabilities, and cross-file detection. It also has a plethora of security rules in the registry. These features will not be included in ast-grep.

herrington_d 3y ago

Why I think semgrep is a security tool different from ast-grep: * Semgrep is security focused. It has many advanced static analysis features in its core product, such as dataflow analysis, symbolic propagation, and semantic equivalence, all of which are useful for security analysis. They are not available in ast-grep. * Semgrep’s pattern syntax also prefers matching more potentially vulnerable semantics than matching precise syntax. Semantic level information is the better level of abstraction for security model. ast-grep, on the other hand, sticks to faithfully translating users' queries syntactically. * Semgrep has a one-off search and rewrite feature, but it is not its primary focus. The CLI is a bit slow compared to other tools. ast-grep strives to be a fast CLI tool. * Semgrep has a product matrix for vulnerability detection: detecting secrets, supply chain vulnerabilities, and cross-file detection. It also has a plethora of security rules in the registry. These features will not be included in ast-grep.