From 21c442050aabae068a257d31c4868bdbdde8ee23 Mon Sep 17 00:00:00 2001
From: Enze Chi <enze.chi@gmail.com>
Date: Thu, 4 Apr 2019 16:20:48 +1100
Subject: [PATCH] Add go-run-args to pass command line arguments to `go run`

When executing the main function which requires command line arguments, user can
set `go-run-args` to pass command line arguments to compiled binary.

The example below demonstrates how to pass command line arguments by setting
`go-run-args` as file local variable:

package main

import (
	"fmt"
	"os"
	"strconv"
)

func main() {
	//Atoi converts a string to an int
	fmt.Println("Arguments:", os.Args)
	a, _ := strconv.Atoi(os.Args[1])
	b, _ := strconv.Atoi(os.Args[2])

	result := sum(a, b)
	fmt.Printf("The sum of %d and %d is %d\n", a, b, result)
}

func sum(a, b int) int {
	return a + b
}

// Local Variables:
// go-run-args: "10 5"
// End:
---
 CHANGELOG.develop          | 4 +++-
 layers/+lang/go/README.org | 9 +++++++++
 layers/+lang/go/config.el  | 3 +++
 layers/+lang/go/funcs.el   | 6 ++++--
 4 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.develop b/CHANGELOG.develop
index cc80002a9..d33779ae0 100644
--- a/CHANGELOG.develop
+++ b/CHANGELOG.develop
@@ -805,6 +805,7 @@ Other:
     (thanks to Boris Buliga)
   - Cleanup =which-key= by removing obsolete entries and adding some missing
     ones (thans to duianto)
+  - Add =go-run-args= to pass command line arguments to `go run`
 - Fixed:
   - Fixed ~h~ key binding in compilation and grep buffers (thanks to Sylvain
     Benner)
@@ -2170,4 +2171,5 @@ Other:
   Hoffmann, Xiang Ji, Yi Liu, zer09, Zhige Xin)
 *** Release notes summarized
   Thanks to: Grant Shangreaux, Songpeng Zu, Igor Almeida, Miciah Dashiel Butler
-  Masters, Abhishek(Compro) Prasad, Deepak Khidia, Ward Harris, Jiahao Jiang
+  Masters, Abhishek(Compro) Prasad, Deepak Khidia, Ward Harris, Jiahao Jiang,
+  Enze Chi
diff --git a/layers/+lang/go/README.org b/layers/+lang/go/README.org
index 38b5dcb8a..ee1a0b8a5 100644
--- a/layers/+lang/go/README.org
+++ b/layers/+lang/go/README.org
@@ -153,6 +153,15 @@ or
   (go :variables gofmt-command "goimports")
 #+END_SRC
 
+To run current main package with command line arguments, set the value of
+=go-run-args= as file local variable, e.g.
+
+#+BEGIN_SRC emacs-lisp
+  // Local Variables:
+  // go-run-args: "--output run.log"
+  // End:
+#+END_SRC
+
 ** Indentation
 By default, the tab width in Go mode is 8 spaces. To use a different value set
 the layer variable =go-tab-width=, e.g.
diff --git a/layers/+lang/go/config.el b/layers/+lang/go/config.el
index 5bba79b3f..8b3e78fb7 100644
--- a/layers/+lang/go/config.el
+++ b/layers/+lang/go/config.el
@@ -39,3 +39,6 @@
 
 (defvar go-test-verbose nil
   "Control verbosity of `go test` output")
+
+(defvar go-run-args ""
+  "Additional arguments to by supplied to `go run` during runtime.")
diff --git a/layers/+lang/go/funcs.el b/layers/+lang/go/funcs.el
index a9064f38c..d714c7928 100644
--- a/layers/+lang/go/funcs.el
+++ b/layers/+lang/go/funcs.el
@@ -115,9 +115,11 @@
 (defun spacemacs/go-run-main ()
   (interactive)
   (shell-command
-   (format "go run %s"
+   (format "go run %s %s"
            (shell-quote-argument (or (file-remote-p (buffer-file-name (buffer-base-buffer)) 'localname)
-                                     (buffer-file-name (buffer-base-buffer)))))))
+                                     (buffer-file-name (buffer-base-buffer))))
+           go-run-args)))
+
 (defun spacemacs/go-packages-gopkgs ()
   "Return a list of all Go packages, using `gopkgs'."
   (sort (process-lines "gopkgs") #'string<))