gofmt from stdin

[bsr]

Hello,

What is the best way to gofmt a program which is read from stdin. I am not too familiar with piping, but this almost work

echo "package foo; type T struct {

Var1    type1   `json:"var,omitempty"` // somecomment1 

}" | gofmt

this outputs

-bash: json:var,omitempty: command not found

package foo

type T struct {

Var1 type1 // somecomment1

}

how can I make it to use field tag? or is there a better way than echoing the string.

For the context, I am calling this through node.js

function format(src) {

            var cmd = 'echo "' + src + '" | gofmt'

            child_process.exec(cmd, function (err, stdout, stderr) { 

            ....

           });

}

where src is the program.

[Wael M. Nasreddine]

On Sat, Sep 27, 2014 at 6:36 PM, bsr <bsr...@gmail.com> wrote:

Hello,

What is the best way to gofmt a program which is read from stdin. I am not too familiar with piping, but this almost work

echo "package foo; type T struct {

Var1    type1   `json:"var,omitempty"` // somecomment1 

}" | gofmt

The backtick in here (the one right before the word json) is being evaluated as a subshell, so you need to wrap everything in a single quote rather than a double quote, which also means you need to escape inner double quotes with a backslash.

 

this outputs

-bash: json:var,omitempty: command not found

package foo

type T struct {

Var1 type1 // somecomment1

}

how can I make it to use field tag? or is there a better way than echoing the string.

For the context, I am calling this through node.js

function format(src) {

            var cmd = 'echo "' + src + '" | gofmt'

            child_process.exec(cmd, function (err, stdout, stderr) { 

            ....

           });

}

where src is the program.

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[bsr]

thank you. it worked, I only changed this line 

    var cmd = "echo '" + d + "' | gofmt";

I didn't have to escape the double quotes (if I do, the backslash is in the output).

thanks again for your help.

hope echoing like this is still the best way to read from stdin.

[luz...@gmail.com]

On Sunday, September 28, 2014 4:02:18 AM UTC+2, bsr wrote:

hope echoing like this is still the best way to read from stdin.

No, it's not the best way to write to stdin from Node.js. Try this:

var exec = require('child_process').exec;

var src = 'package main\nimport "fmt"\nfunc main() {\nfmt.Println("hello, world")\n}';

var gofmt = exec('gofmt', function (err, stdout, stderr) {
  console.log(stdout);
});
gofmt.stdin.setEncoding = 'utf-8';
gofmt.stdin.write(src);
gofmt.stdin.end();

[bsr]

looks much better .. thank you. 

On a side note, it works, but "setEncoding" is for readable stream (process.stdin). but as per the manual, child_process.stdin, writable stream, don't have it. 

http://nodejs.org/api/stream.html

thanks again for your help.