Function frequency: Difference between revisions

=={{header|Go}}==

Only crude approximation is currently easy in Go. The following parses source code, looks for function call syntax (an expression followed by an argument list) and prints the expression.

<lang go>package main

import (

"fmt"

"go/ast"

"go/parser"

"go/token"

"io/ioutil"

"os"

)

func main() {

if len(os.Args) != 2 {

fmt.Println("usage ff <go source filename>")

return

}

src, err := ioutil.ReadFile(os.Args[1])

if err != nil {

fmt.Println(err)

return

}

fs := token.NewFileSet()

a, err := parser.ParseFile(fs, os.Args[1], src, 0)

if err != nil {

fmt.Println(err)

return

}

f := fs.File(a.Pos())

m := make(map[string]int)

ast.Inspect(a, func(n ast.Node) bool {

if ce, ok := n.(*ast.CallExpr); ok {

start := f.Offset(ce.Pos())

end := f.Offset(ce.Lparen)

m[string(src[start:end])]++

}

return true

})

for k, v := range m {

fmt.Println(v, k)

}

}</lang>

Output, when run on source code above:

<pre>

4 fmt.Println

1 string

1 a.Pos

1 ast.Inspect

1 ioutil.ReadFile

1 len

2 f.Offset

1 token.NewFileSet

1 ce.Pos

1 make

1 fs.File

1 parser.ParseFile

</pre>