support for env var referencing from command line

Fixes #16

Author: starpit

app/content/js/repl.js

@@ -453,8 +453,31 @@ self.pexec = (command, execOptions) => self.exec(command, Object.assign({ echo:
 
 const patterns = {
     commentLine: /\s*#.*$/,
+    dash: /-([^\s]*)/,
     whitespace: /\s/
 }
+
+/**
+ * Escape the given value so that it is compatible with command line execution
+ *
+ */
+const escape = str => str.replace(patterns.dash, "'-$1'")
+
+/**
+  * Resolve the given string as a possible reference to an environment
+  * variable; e.g. $FOO should resolve to 3 if process.env.FOO has
+  * value 3.
+  *
+  */
+const resolveEnvVar = variable => {
+    const envValue = process.env[variable.substring(1)]
+    return envValue ? escape(envValue) : variable
+}
+
+/**
+ * Split the given string into an argv
+ *
+ */
 const split = (str, removeOuterQuotes=true) => {
     const A = [],
           stack = []
@@ -466,7 +489,7 @@ const split = (str, removeOuterQuotes=true) => {
 
         if (stack.length === 0 && char.match(patterns.whitespace)) {
             if (cur.length > 0) {
-                A.push(cur)
+                A.push(resolveEnvVar(cur))
                 cur = ''
             }
             continue
@@ -507,7 +530,7 @@ const split = (str, removeOuterQuotes=true) => {
     }
 
     if (cur.length > 0) {
-        A.push(cur)
+        A.push(resolveEnvVar(cur))
     }
 
     return A

tests/data/echo.js

@@ -0,0 +1 @@
+const main = x=>x

tests/tests/passes/02/headless.js

@@ -23,10 +23,10 @@ const path = require('path'),
       fsh = path.join(__dirname, '../../../../app/bin/fsh')
 
 const cli = {
-    do: cmd => new Promise((resolve, reject) => {
+    do: (cmd, env={}) => new Promise((resolve, reject) => {
         const command = `${fsh} ${cmd} --no-color`
 
-        exec(command, (err, stdout, stderr) => {
+        exec(command, { env: Object.assign({}, process.env, env) }, (err, stdout, stderr) => {
             if (err) {
                 resolve({ code: err.code, output: stdout.trim().concat(stderr) })
             } else {
@@ -125,4 +125,8 @@ describe('Headless mode', function() {
     it('should create an app', () => cli.do('app create seq ./data/fsm.json')
        .then(cli.expectOK('ok: updated app seq\n', { exact: true }))
        .catch(common.oops(this)))
+
+    it('should create an action with an env var parameter', () => cli.do('action create envfun ./data/echo.js -p fun $FUN', { FUN: 3 })
+       .then(cli.expectOK('ok: updated action envfun\n', { exact: true }))
+       .catch(common.oops(this)))
 })