Module replacer 

Code Replacement and Transformation

Tools for replacing and transforming matched AST nodes with new content.

Core Concepts

• Replacer - Trait for generating replacement content from matched nodes
• Template-based replacement using meta-variables (e.g., "let $VAR = $VALUE")
• Structural replacement using other AST nodes
• Automatic indentation handling to preserve code formatting

Built-in Replacers

Several types implement Replacer out of the box:

• &str - Template strings with meta-variable substitution
• Root - Replace with entire AST trees
• Node - Replace with specific nodes

Examples

Template Replacement

let mut ast = Language::Tsx.ast_grep("var x = 42;");

// Replace using a template string
ast.replace("var $NAME = $VALUE", "const $NAME = $VALUE");
println!("{}", ast.generate()); // "const x = 42;"

Structural Replacement

let mut target = Language::Tsx.ast_grep("old_function();");
let replacement = Language::Tsx.ast_grep("new_function(42)");

// Replace with another AST
target.replace("old_function()", replacement);
println!("{}", target.generate()); // "new_function(42);"

Re-exports

pub use crate::source::Content;

Enums

TemplateFix

TemplateFixError

Traits

Replacer

Generate replacement content for matched AST nodes.