Created vccdiscover utility for vcc auto-discovery

tools/vccexe/vccdiscover.nim

@@ -0,0 +1,76 @@
+import strutils, os, vccenv
+
+type
+  VccVersion* = enum
+    vccUndefined = (0, ""),
+    vcc90  =  vs90, # Visual Studio 2008
+    vcc100 = vs100, # Visual Studio 2010
+    vcc110 = vs110, # Visual Studio 2012
+    vcc120 = vs120, # Visual Studio 2013
+    vcc140 = vs140  # Visual Studio 2015
+
+proc discoverVccVcVarsAllPath*(version: VccVersion = vccUndefined): string =
+  # TODO: Attempt discovery using vswhere utility.
+
+  # Attempt discovery through VccEnv 
+  # (Trying Visual Studio Common Tools Environment Variables)
+  result = vccEnvVcVarsAllPath(cast[VccEnvVersion](version))
+  if result.len > 0:
+    return
+
+  # All attempts to dicover vcc failed
+
+when isMainModule:
+  const
+    helpText = """
++-----------------------------------------------------------------+
+|        Microsoft C/C++ Compiler Discovery Utility               |
+|            (c) 2017 Fredrik Hoeisaether Rasch                   |
++-----------------------------------------------------------------+
+
+Discovers the path to the Developer Command Prompt for the 
+specified versions, or attempts to discover the latest installed 
+version if no specific version is requested.
+
+Usage:
+  vccdiscover [<version>...]
+Arguments:
+  <version>   Optionally specify the version to discover
+    Valid values: 0, 90, 100, 110, 120, 140
+    A value of 0 will discover the latest installed SDK
+"""
+  var quitValue = 0
+  let args = commandLineParams()
+  if args.len < 1:
+    let path = discoverVccVcVarsAllPath()
+    if path.len < 1:
+      echo "latest: VCC installation discovery failed."
+      quitValue = 1
+    else:
+      echo "latest: " & path
+
+  for argv in args:
+    # Strip leading hyphens or slashes, if someone tries -?, /?, --help or /help
+    if argv.len < 1:
+      continue
+    var argvValue = argv
+    while argvValue[0] == '-' or argvValue[0] == '/':
+      argvValue = argvValue.substr(1)
+    if argvValue.len < 1:
+      continue
+
+    if cmpIgnoreCase(argvValue, "help") == 0 or cmpIgnoreCase(argvValue, "?") == 0:
+      echo helpText
+      continue
+    
+    let version = cast[VccVersion](parseInt(argvValue))
+    let path = discoverVccVcVarsAllPath(version)
+    var head = $version
+    if head.len < 1:
+      head = "latest"
+    if path.len < 1:
+      echo head & ": VCC installation discovery failed."
+      inc quitValue
+    else:
+      echo "$1: $2" % [head, path]
+  quit quitValue