gogrep
GO111MODULE=on go get mvdan.cc/gogrep
Search for Go code using syntax trees.
gogrep -x 'if $x != nil { return $x, $*_ }'
Note that this project is no longer being developed. See #64 for more details.
Instructions
usage: gogrep commands [packages]
A command is of the form "-A pattern", where -A is one of:
-x find all nodes matching a pattern
-g discard nodes not matching a pattern
-v discard nodes matching a pattern
-a filter nodes by certain attributes
-s substitute with a given syntax tree
-w write source back to disk or stdout
A pattern is a piece of Go code which may include wildcards. It can be:
a statement (many if split by semicolons)
an expression (many if split by commas)
a type expression
a top-level declaration (var, func, const)
an entire file
Wildcards consist of $ and a name. All wildcards with the same name
within an expression must match the same node, excluding "_". Example:
$x.$_ = $x // assignment of self to a field in self
If * is before the name, it will match any number of nodes. Example:
fmt.Fprintf(os.Stdout, $*_) // all Fprintfs on stdout
* can also be used to match optional nodes, like:
for $*_ { $*_ } // will match all for loops
if $*_; $b { $*_ } // will match all ifs with condition $b
The nodes resulting from applying the commands will be printed line by line to standard output.
Here are two simple examples of the -a operand:
gogrep -x '$x + $y' // will match both numerical and string "+" operations
gogrep -x '$x + $y' -a 'type(string)' // matches only string concatenations