configuration system supports %= to access environment variables

compiler/commands.nim

@@ -52,7 +52,7 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo)
 
 const
   HelpMessage = "Nim Compiler Version $1 (" & CompileDate & ") [$2: $3]\n" &
-      "Copyright (c) 2006-2014 by Andreas Rumpf\n"
+      "Copyright (c) 2006-2015 by Andreas Rumpf\n"
 
 const 
   Usage = slurp"doc/basicopt.txt".replace("//", "")

compiler/nimconf.nim

@@ -11,7 +11,7 @@
 
 import 
   llstream, nversion, commands, os, strutils, msgs, platform, condsyms, lexer, 
-  options, idents, wordrecg
+  options, idents, wordrecg, strtabs
 
 # ---------------- configuration file parser -----------------------------
 # we use Nim's scanner here to safe space and work
@@ -82,17 +82,17 @@ proc doElif(L: var TLexer, tok: var TToken) =
 proc jumpToDirective(L: var TLexer, tok: var TToken, dest: TJumpDest) = 
   var nestedIfs = 0
   while true: 
-    if (tok.ident != nil) and (tok.ident.s == "@"): 
+    if tok.ident != nil and tok.ident.s == "@":
       ppGetTok(L, tok)
       case whichKeyword(tok.ident)
       of wIf: 
         inc(nestedIfs)
       of wElse: 
-        if (dest == jdElseEndif) and (nestedIfs == 0): 
+        if dest == jdElseEndif and nestedIfs == 0:
           doElse(L, tok)
           break 
       of wElif: 
-        if (dest == jdElseEndif) and (nestedIfs == 0): 
+        if dest == jdElseEndif and nestedIfs == 0:
           doElif(L, tok)
           break 
       of wEnd: 
@@ -121,7 +121,8 @@ proc parseDirective(L: var TLexer, tok: var TToken) =
   of wEnd: doEnd(L, tok)
   of wWrite:
     ppGetTok(L, tok)
-    msgs.msgWriteln(tokToStr(tok))
+    msgs.msgWriteln(strtabs.`%`(tokToStr(tok), options.gConfigVars,
+                                {useEnvironment, useKey}))
     ppGetTok(L, tok)
   else:
     case tok.ident.s.normalize
@@ -178,9 +179,10 @@ proc parseAssignment(L: var TLexer, tok: var TToken) =
     if tok.tokType == tkBracketRi: confTok(L, tok)
     else: lexMessage(L, errTokenExpected, "']'")
     add(val, ']')
-  if tok.tokType in {tkColon, tkEquals}: 
+  let percent = tok.ident.id == getIdent("%=").id
+  if tok.tokType in {tkColon, tkEquals} or percent: 
     if len(val) > 0: add(val, ':')
-    confTok(L, tok)           # skip ':' or '='
+    confTok(L, tok)           # skip ':' or '=' or '%'
     checkSymbol(L, tok)
     add(val, tokToStr(tok))
     confTok(L, tok)           # skip symbol
@@ -189,7 +191,11 @@ proc parseAssignment(L: var TLexer, tok: var TToken) =
       checkSymbol(L, tok)
       add(val, tokToStr(tok))
       confTok(L, tok)
-  processSwitch(s, val, passPP, info)
+  if percent:
+    processSwitch(s, strtabs.`%`(val, options.gConfigVars,
+                                {useEnvironment, useEmpty}), passPP, info)
+  else:
+    processSwitch(s, val, passPP, info)
 
 proc readConfigFile(filename: string) =
   var

config/nim.cfg

@@ -5,7 +5,8 @@
 
 # You may set environment variables with
 # @putenv "key" "val"
-# Environment variables cannot be used in the options, however!
+# Environment variables can be accessed like so:
+#  gcc.path %= "$CC_PATH"
 
 cc = gcc
 
@@ -21,6 +22,7 @@ mips.linux.gcc.linkerexe = "mips-openwrt-linux-gcc"
 @end
 
 path="$lib/core"
+
 path="$lib/pure"
 path="$lib/pure/collections"
 path="$lib/pure/concurrency"

lib/pure/strtabs.nim

@@ -158,7 +158,7 @@ proc getValue(t: StringTableRef, flags: set[FormatFlag], key: string): string =
   else: result = ""
   if result.len == 0:
     if useKey in flags: result = '$' & key
-    elif not (useEmpty in flags): raiseFormatException(key)
+    elif useEmpty notin flags: raiseFormatException(key)
 
 proc newStringTable*(mode: StringTableMode): StringTableRef {.
   rtl, extern: "nst$1".} =