--- /dev/null
+#!/usr/bin/env bash
+# Copyright 2010 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+# Using all the non-test *.go files in the named directory, write
+# out a file /tmp/$USER.try.go to evaluate the expressions on the
+# command line, perhaps to discover a function or method that
+# gives the desired results. See usage message.
+# Compile the program and run it.
+
+# Makes egrep,grep work better in general if we put them
+# in ordinary C mode instead of what the current language is.
+unset LANG
+export LC_ALL=C
+export LC_CTYPE=C
+
+export GOROOT=${GOROOT:-"@@GOROOT@@"}
+eval $(gomake -j1 --no-print-directory -f "$GOROOT"/src/Make.inc go-env)
+if [ -z "$O" ]; then
+ echo 'missing $O - maybe no Make.$GOARCH?' 1>&2
+ exit 2
+fi
+
+# Allow overrides
+GC="${_GC:-$GC} -I _test"
+GL="${GL:-$LD} -L _test"
+AS="$AS"
+CC="$CC"
+LD="$LD"
+export GC GL O AS CC LD
+
+# Macros for tab and quotes for easier readability.
+T=' '
+BQ='`'
+SQ="'"
+DQ='"'
+SD="$SQ$DQ"
+DS="$DQ$SQ"
+
+usage="usage: gotry [packagedirectory] expression ...
+Given one expression, gotry attempts to evaluate that expression.
+Given multiple expressions, gotry treats them as a list of arguments
+and result values and attempts to find a function in the package
+that, given the first few expressions as arguments, evaluates to
+the remaining expressions as results. If the first expression has
+methods, it will also search for applicable methods.
+
+If there are multiple expressions, a package directory must be
+specified. If there is a package argument, the expressions are
+evaluated in an environment that includes
+ import . ${DQ}packagedirectory${DQ}
+
+Examples:
+ gotry 3+4
+ # evaluates to 7
+ gotry strings ${SD}abc${DS} ${SD}c${DS} 7-5
+ # finds strings.Index etc.
+ gotry regexp ${SQ}MustCompile(${DQ}^[0-9]+${DQ})${SQ} ${SD}12345${DS} true
+ # finds Regexp.MatchString
+
+"
+
+function fail() {
+ echo 2>&1 "$@"
+ exit 2
+}
+
+case $# in
+ 0)
+ fail "$usage"
+ ;;
+ *)
+ case "$1" in
+ -*help|-*'?'|'?')
+ fail "$usage"
+ esac
+ if test -d "$GOROOT/src/pkg/$1"
+ then
+ pkg=$(basename $1)
+ dir=$GOROOT/src/pkg/$1
+ importdir=$1
+ shift
+ case "$pkg" in
+ os|syscall)
+ fail "gotry: cannot try packages os or syscall; they are too dangerous"
+ esac
+ fi
+ ;;
+esac
+
+spaces='[ ][ ]*'
+
+function getFunctions() {
+ if [ "$pkg" = "" ]
+ then
+ return
+ fi
+ for file in $dir/*.go
+ do
+ case $file in
+ *_test*)
+ continue
+ esac
+ grep "func$spaces[A-Z]" $file | # TODO: should be Unicode upper case
+ sed "s/func$spaces//;s/(.*//"
+ done | sort -u
+}
+
+# Generate list of public functions.
+functions=$(getFunctions)
+
+# Write file to compile
+rm -f /tmp/$USER.try.go
+(
+cat <<'!'
+package main
+
+import (
+ "os"
+ "try"
+!
+
+if [ "$pkg" != "" ]
+then
+ echo "$T" . '"'$importdir'"'
+fi
+
+cat <<!
+)
+func main() {
+ try.Main("$pkg", firstArg, functions, args)
+}
+var functions = map[string] interface{}{
+!
+
+for i in $functions
+do
+ echo "$T"'"'$i'": '$i','
+done
+echo "}"
+
+echo 'var args = []interface{}{'
+
+if [ $# = 1 ]
+then
+ echo "${T}toSlice($1)",
+else
+for i
+ do
+ echo "$T$i",
+ done
+fi
+echo "}"
+
+cat <<!
+var firstArg = $BQ$1$BQ
+var _ os.Error
+func toSlice(a ...interface{}) []interface{} { return a }
+!
+
+)>/tmp/$USER.try.go
+
+$GC -o /tmp/$USER.try.$O /tmp/$USER.try.go &&
+$GL -o /tmp/$USER.try /tmp/$USER.try.$O &&
+/tmp/$USER.try "_$@"
+rm -f /tmp/$USER.try /tmp/$USER.try.go /tmp/$USER.try.$O
--- /dev/null
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package try contains the executable part of the gotry command.
+// It is not intended for general use.
+package try
+
+import (
+ "fmt"
+ "io"
+ "os"
+ "reflect"
+ "unicode"
+)
+
+var output io.Writer = os.Stdout // redirected when testing
+
+// Main is called directly from the gotry-generated Go source file to perform
+// the evaluations.
+func Main(pkg, firstArg string, functions map[string]interface{}, args []interface{}) {
+ switch len(args) {
+ case 0:
+ // Nothing to do.
+ case 1:
+ // Compiler has already evaluated the expression; just print the result.
+ printSlice(firstArg, args)
+ default:
+ // See if methods satisfy the expressions.
+ tryMethods(pkg, firstArg, args)
+ // See if functions satisfy the expressions.
+ for name, fn := range functions {
+ tryFunction(pkg, name, fn, args)
+ }
+ }
+}
+
+// printSlice prints the zeroth element of the args slice, which should (by construction)
+// itself be a slice of interface{}.
+func printSlice(firstArg string, args []interface{}) {
+ // Args should be length 1 and a slice.
+ if len(args) != 1 {
+ return
+ }
+ arg, ok := args[0].([]interface{})
+ if !ok {
+ return
+ }
+ fmt.Fprintf(output, "%s = ", firstArg)
+ if len(arg) > 1 {
+ fmt.Fprint(output, "(")
+ }
+ for i, a := range arg {
+ if i > 0 {
+ fmt.Fprint(output, ", ")
+ }
+ fmt.Fprintf(output, "%#v", a)
+ }
+ if len(arg) > 1 {
+ fmt.Fprint(output, ")")
+ }
+ fmt.Fprint(output, "\n")
+}
+
+// tryMethods sees if the zeroth arg has methods, and if so treats them as potential
+// functions to satisfy the remaining arguments.
+func tryMethods(pkg, firstArg string, args []interface{}) {
+ defer func() { recover() }()
+ // Is the first argument something with methods?
+ v := reflect.NewValue(args[0])
+ typ := v.Type()
+ if typ.NumMethod() == 0 {
+ return
+ }
+ for i := 0; i < typ.NumMethod(); i++ {
+ if unicode.IsUpper(int(typ.Method(i).Name[0])) {
+ tryMethod(pkg, firstArg, typ.Method(i), args)
+ }
+ }
+}
+
+// tryMethod converts a method to a function for tryOneFunction.
+func tryMethod(pkg, firstArg string, method reflect.Method, args []interface{}) {
+ rfn := method.Func
+ typ := method.Type
+ name := method.Name
+ tryOneFunction(pkg, firstArg, name, typ, rfn, args)
+}
+
+// tryFunction sees if fn satisfies the arguments.
+func tryFunction(pkg, name string, fn interface{}, args []interface{}) {
+ defer func() { recover() }()
+ rfn := reflect.NewValue(fn).(*reflect.FuncValue)
+ typ := rfn.Type().(*reflect.FuncType)
+ tryOneFunction(pkg, "", name, typ, rfn, args)
+}
+
+// tryOneFunction is the common code for tryMethod and tryFunction.
+func tryOneFunction(pkg, firstArg, name string, typ *reflect.FuncType, rfn *reflect.FuncValue, args []interface{}) {
+ // Any results?
+ if typ.NumOut() == 0 {
+ return // Nothing to do.
+ }
+ // Right number of arguments + results?
+ if typ.NumIn()+typ.NumOut() != len(args) {
+ return
+ }
+ // Right argument and result types?
+ for i, a := range args {
+ if i < typ.NumIn() {
+ if !compatible(a, typ.In(i)) {
+ return
+ }
+ } else {
+ if !compatible(a, typ.Out(i-typ.NumIn())) {
+ return
+ }
+ }
+ }
+ // Build the call args.
+ argsVal := make([]reflect.Value, typ.NumIn()+typ.NumOut())
+ for i, a := range args {
+ argsVal[i] = reflect.NewValue(a)
+ }
+ // Call the function and see if the results are as expected.
+ resultVal := rfn.Call(argsVal[:typ.NumIn()])
+ for i, v := range resultVal {
+ if !reflect.DeepEqual(v.Interface(), args[i+typ.NumIn()]) {
+ return
+ }
+ }
+ // Present the result including a godoc command to get more information.
+ firstIndex := 0
+ if firstArg != "" {
+ fmt.Fprintf(output, "%s.%s(", firstArg, name)
+ firstIndex = 1
+ } else {
+ fmt.Fprintf(output, "%s.%s(", pkg, name)
+ }
+ for i := firstIndex; i < typ.NumIn(); i++ {
+ if i > firstIndex {
+ fmt.Fprint(output, ", ")
+ }
+ fmt.Fprintf(output, "%#v", args[i])
+ }
+ fmt.Fprint(output, ") = ")
+ if typ.NumOut() > 1 {
+ fmt.Fprint(output, "(")
+ }
+ for i := 0; i < typ.NumOut(); i++ {
+ if i > 0 {
+ fmt.Fprint(output, ", ")
+ }
+ fmt.Fprintf(output, "%#v", resultVal[i].Interface())
+ }
+ if typ.NumOut() > 1 {
+ fmt.Fprint(output, ")")
+ }
+ fmt.Fprintf(output, " // godoc %s %s\n", pkg, name)
+}
+
+// compatible reports whether the argument is compatible with the type.
+func compatible(arg interface{}, typ reflect.Type) bool {
+ if reflect.Typeof(arg) == typ {
+ return true
+ }
+ if arg == nil {
+ // nil is OK if the type is an interface.
+ if _, ok := typ.(*reflect.InterfaceType); ok {
+ return true
+ }
+ }
+ return false
+}
--- /dev/null
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package try
+
+import (
+ "bytes"
+ "regexp" // Used as the package to try.
+ "testing"
+)
+
+// The global functions in package regexp at time of writing.
+// Doesn't need to be updated unless the entries in this list become invalid.
+var functions = map[string]interface{}{
+ "Compile": regexp.Compile,
+ "Match": regexp.Match,
+ "MatchString": regexp.MatchString,
+ "MustCompile": regexp.MustCompile,
+ "QuoteMeta": regexp.QuoteMeta,
+}
+
+// A wraps arguments to make the test cases nicer to read.
+func A(args ...interface{}) []interface{} {
+ return args
+}
+
+type Test struct {
+ firstArg string // only needed if there is exactly one argument
+ result string // minus final newline; might be just the godoc string
+ args []interface{}
+}
+
+var testRE = regexp.MustCompile("a(.)(.)d")
+
+var tests = []Test{
+ // A simple expression. The final value is a slice in case the expression is multivalue.
+ Test{"3+4", "3+4 = 7", A([]interface{}{7})},
+ // A search for a function.
+ Test{"", "regexp QuoteMeta", A("([])", `\(\[\]\)`)},
+ // A search for a function with multiple return values.
+ Test{"", "regexp MatchString", A("abc", "xabcd", true, nil)},
+ // Searches for methods.
+ Test{"", "regexp MatchString", A(testRE, "xabcde", true)},
+ Test{"", "regexp NumSubexp", A(testRE, 2)},
+}
+
+func TestAll(t *testing.T) {
+ re := regexp.MustCompile(".*// godoc ")
+ for _, test := range tests {
+ b := new(bytes.Buffer)
+ output = b
+ Main("regexp", test.firstArg, functions, test.args)
+ expect := test.result + "\n"
+ got := re.ReplaceAllString(b.String(), "")
+ if got != expect {
+ t.Errorf("expected %q; got %q", expect, got)
+ }
+ }
+}