Find function declarations with names of certain pattern

• Playground Link

Description

ast-grep can find function declarations by their names. But not all names can be matched by a meta variable pattern. For instance, you cannot use a meta variable pattern to find function declarations whose names start with a specific prefix, e.g. TestAbs with the prefix Test. Attempting Test$_ will fail because it is not a valid syntax.

Instead, you can use a YAML rule to use the regex atomic rule.

YAML

id: test-functions
language: go
rule:
  kind: function_declaration
  has:
    field: name
    regex: Test.*

Example

package abs
import "testing"
func TestAbs(t *testing.T) {
    got := Abs(-1)
    if got != 1 {
        t.Errorf("Abs(-1) = %d; want 1", got)
    }
}

Contributed by

kevinkjt2000 on Discord.