Add pipe support

Shell supports pipes | now. For now cat is the only command that
actually uses stdin though. Also fixed some other consistency issues and
a few missing tests.

See #15.

README.md

@@ -87,8 +87,9 @@ for bundling and minification in your own workflow.
   - [See below](#the-state-object)
 
 
-### Built-in commands and flags
+### Built-in features, commands and flags
 
+- pipes `|`
 - `ls -l -a`
 - `cd`
 - `pwd`

index.html

@@ -146,9 +146,6 @@
         if (e.which !== ENTER) {
           return
         }
-        if (!input.value.length) {
-          return
-        }
         run(input.value).then(function () {
           input.value = ''
           document.body.scrollTop = 10e6

src/commands/cat.js

@@ -1,9 +1,12 @@
-var addLineNumbers = require('../utils/lineNumber')
+var lineNumber = require('../utils/lineNumber')
 
 var numColumnWidth = 6
 var numberFlag = '-n'
 
 function cat (env, args) {
+  // Ignore command name
+  args.shift()
+
   var exitCode = 0
   var numberFlagIndex = args.findIndex(function (arg) {
     return arg === numberFlag
@@ -12,6 +15,26 @@ function cat (env, args) {
   if (showNumbers) {
     args.splice(numberFlagIndex, 1)
   }
+
+  if (!args.length) {
+    var num = 1
+    return {
+      input: function (str) {
+        str.split('\n').forEach(function (l) {
+          if (!l) {
+            return
+          }
+          var line = showNumbers ? lineNumber.addLineNumber(numColumnWidth, num, l) : l
+          num++
+          env.output(line + '\n')
+        })
+      },
+      close: function () {
+        env.exit(exitCode)
+      }
+    }
+  }
+
   Promise
     .all(args.map(function (path) {
       return env.system.read(path).then(null, function (err) {
@@ -20,13 +43,10 @@ function cat (env, args) {
       })
     }))
     .then(function (contents) {
-      if (!showNumbers) {
-        return contents
-      }
-      return addLineNumbers(numColumnWidth, contents)
-    })
-    .then(function (contents) {
-      env.output(contents.join('\n'))
+      var lines = showNumbers ? lineNumber.addLineNumbers(numColumnWidth, contents) : contents
+      lines.forEach(function (line) {
+        env.output(line + '\n')
+      })
       env.exit(exitCode)
     })
 }

src/commands/cd.js

@@ -1,4 +1,7 @@
 function cd (env, args) {
+  // Ignore command name
+  args.shift()
+
   var path = args[0] || '/home/' + env.system.state.user
 
   env.system.changeDir(path).then(

src/commands/cp.js

@@ -1,6 +1,9 @@
 var SINGLE_COPY = 'SINGLE_COPY'
 
 function cp (env, args) {
+  // Ignore command name
+  args.shift()
+
   var rFlagIndex = args.findIndex(function (arg) {
     return arg === '-r' || arg === '-R'
   })

src/commands/history.js

@@ -1,11 +1,11 @@
-var addLineNumbers = require('../utils/lineNumber')
+var lineNumber = require('../utils/lineNumber')
 
 // default width for number column
 var numColumnWidth = 5
 
 function history (env) {
   env.system.getHistory().then(function (history) {
-    env.output(addLineNumbers(numColumnWidth, history).join('\n'))
+    env.output(lineNumber.addLineNumbers(numColumnWidth, history).join('\n'))
     env.exit()
   })
 }

src/commands/ls.js

@@ -7,6 +7,9 @@ var disclaimer =
   'On a real system you would also see file permissions, user, group, block size and more.'
 
 function ls (env, args) {
+  // Ignore command name
+  args.shift()
+
   var aFlagIndex = args.findIndex(function (arg) {
     return arg === '-a'
   })

src/commands/mkdir.js

@@ -1,4 +1,7 @@
 function mkdir (env, args) {
+  // Ignore command name
+  args.shift()
+
   if (!args.length) {
     env.error('mkdir: missing operand')
     env.exit(1)

src/commands/mv.js

@@ -1,6 +1,9 @@
 var SINGLE_COPY = 'SINGLE_COPY'
 
 function mv (env, args) {
+  // Ignore command name
+  args.shift()
+
   var nFlagIndex = args.findIndex(function (arg) {
     return arg === '-n'
   })

src/commands/pwd.js

@@ -1,4 +1,4 @@
-function pwd (env, args) {
+function pwd (env) {
   env.system.getDir().then(function (dir) {
     env.output(dir)
     env.exit()

src/commands/rm.js

@@ -1,4 +1,7 @@
 function rm (env, args) {
+  // Ignore command name
+  args.shift()
+
   var rFlagIndex = args.findIndex(function (arg) {
     return arg.toLowerCase() === '-r'
   })

src/commands/rmdir.js

@@ -1,4 +1,7 @@
 function rmdir (env, args) {
+  // Ignore command name
+  args.shift()
+
   if (!args.length) {
     env.error('rmdir: missing operand')
     env.exit(1)

src/commands/touch.js

@@ -1,4 +1,7 @@
 function touch (env, args) {
+  // Ignore command name
+  args.shift()
+
   if (!args.length) {
     env.error('touch: missing file operand')
     env.exit(1)

src/index.js

@@ -30,32 +30,75 @@ function bashEmulator (initialState) {
     state: state,
 
     run: function (input) {
-      var args = input.split(' ')
-      var cmd = args.shift()
       state.history.push(input)
-      if (!commands[cmd]) {
-        return Promise.reject(cmd + ': command not found')
+
+      var argsList = input.split('|').map(function (pipe) {
+        var args = pipe.trim().split(' ').filter(function (s) {
+          return s
+        })
+        return args
+      })
+
+      if (argsList.length === 1 && !argsList[0].length) {
+        return Promise.resolve('\n')
+      }
+
+      if (!argsList[argsList.length - 1][0]) {
+        return Promise.reject('syntax error: unexpected end of file')
+      }
+
+      if (argsList.find(function (a) { return !a.length })) {
+        return Promise.reject("syntax error near unexpected token `|'")
+      }
+
+      var nonExistent = argsList.filter(function (args) {
+        var cmd = args[0]
+        return !commands[cmd]
+      })
+      if (nonExistent.length) {
+        return Promise.reject(nonExistent.map(function (args) {
+          return args[0] + ': command not found'
+        }).join('\n'))
       }
+
       var result = ''
+
       return new Promise(function (resolve, reject) {
-        commands[cmd]({
-          output: function (str) {
-            result += str
-          },
-          // NOTE: For now we just redirect stderr to stdout
-          error: function (str) {
-            result += str
-          },
-          // NOTE: For now we don't use specific error codes
-          exit: function (code) {
-            if (code) {
-              reject(result)
-            } else {
-              resolve(result)
-            }
-          },
-          system: emulator
-        }, args)
+        var pipes = argsList.map(function (args, idx) {
+          var isLast = idx === argsList.length - 1
+          return commands[args[0]]({
+            output: function (str) {
+              if (isLast) {
+                result += str
+                return
+              }
+              var nextInput = pipes[idx + 1] && pipes[idx + 1].input
+              if (nextInput) {
+                nextInput(str)
+              }
+            },
+            // NOTE: For now we just redirect stderr to stdout
+            error: function (str) {
+              result += str
+            },
+            // NOTE: For now we don't use specific error codes
+            exit: function (code) {
+              if (isLast) {
+                if (code) {
+                  reject(result)
+                } else {
+                  resolve(result)
+                }
+                return
+              }
+              var nextClose = pipes[idx + 1] && pipes[idx + 1].close
+              if (nextClose) {
+                nextClose()
+              }
+            },
+            system: emulator
+          }, args)
+        })
       })
     },
 

src/utils/lineNumber.js

@@ -1,10 +1,13 @@
-function addLineNumbers (width, list) {
-  return list.map(function (item, i) {
+function addLineNumber (width, num, line) {
+  var numChars = num.toString().length
+  var space = ' '.repeat(width - numChars)
+  return space + num + '  ' + line
+}
+module.exports.addLineNumber = addLineNumber
+
+module.exports.addLineNumbers = function (width, lines) {
+  return lines.map(function (line, i) {
     var num = i + 1
-    var numChars = num.toString().length
-    var space = ' '.repeat(width - numChars)
-    return space + num + '  ' + item
+    return addLineNumber(width, num, line)
   })
 }
-
-module.exports = addLineNumbers

test/commands/cat.js

@@ -2,7 +2,7 @@ var test = require('tape')
 var bashEmulator = require('../../src')
 
 test('cat', function (t) {
-  t.plan(5)
+  t.plan(7)
 
   var emulator = bashEmulator({
     workingDirectory: '/',
@@ -29,39 +29,51 @@ test('cat', function (t) {
     var res =
       'first\n' +
       'third\n' +
-      'second'
+      'second\n'
     t.equal(output, res, 'cats multiple files')
   })
 
   emulator.run('cat nonexistent /1.txt').then(null, function (err) {
     var res =
       'cat: nonexistent: No such file or directory' +
       '\n' +
-      'first'
+      'first\n'
     t.equal(err, res, 'with errors')
   })
 
   emulator.run('cat -n 1.txt /3.txt /2.txt').then(function (output) {
     var res =
       '     1  first\n' +
       '     2  third\n' +
-      '     3  second'
+      '     3  second\n'
     t.equal(output, res, 'with -n')
   })
 
   emulator.run('cat 1.txt -n /3.txt /2.txt').then(function (output) {
     var res =
       '     1  first\n' +
       '     2  third\n' +
-      '     3  second'
+      '     3  second\n'
     t.equal(output, res, 'with -n in between')
   })
 
   emulator.run('cat 1.txt /3.txt /2.txt -n').then(function (output) {
     var res =
       '     1  first\n' +
       '     2  third\n' +
-      '     3  second'
+      '     3  second\n'
     t.equal(output, res, 'with -n as last')
   })
+
+  emulator.run('cat 1.txt | cat').then(function (output) {
+    var res = 'first\n'
+    t.equal(output, res, 'cat from stdin')
+  })
+
+  emulator.run('cat 1.txt 2.txt | cat -n').then(function (output) {
+    var res =
+      '     1  first\n' +
+      '     2  second\n'
+    t.equal(output, res, 'cat from stdin with -n')
+  })
 })