Merge pull request #4 from jyapayne/configurable_compiler

Add configurable compiler to global section

README.md

@@ -65,6 +65,17 @@ Nimgen only supports the ```gcc``` preprocessor at this time. Support for detect
 
 __Config file__
 
+In all sections below, environment variables are supported via Nim's string interpolation `%` symbol imported from the `strutils` module. Simply use double quotes to enclose any value and put `$` or `${}` around the environment variable name. In addition, the `output` var from the n.global section is available as ${output}. For example:
+
+    [n.global]
+    c_compiler="$CC"
+    cpp_compiler="${CPP}-arm"
+    output="src/path"
+
+    [n.include]
+    "${output}/library/include"
+    "${MY_INCLUDE_PATH}/include"
+
 _[n.global]_
 
 ```output``` = name of the Nimble project once installed, also location to place generated .nim files
@@ -73,6 +84,10 @@ _[n.global]_
 
 ```filter``` = string to identify and recurse into library .h files in #include statements and exclude standard headers
 
+```cpp_compiler``` = string to specify a CPP compiler executable. [default: g++]
+
+```c_compiler``` = string to specify a C compiler executable. [default: gcc]
+
 _[n.include]_
 
 List of all directories, one per line, to include in the search path. This is used by:-

nimgen.nim

@@ -1,5 +1,11 @@
 import nre, os, ospaths, osproc, parsecfg, pegs, ropes, sequtils, streams, strutils, tables
 
+const
+  cCompilerEnv = "CC"
+  cppCompilerEnv = "CPP"
+  defaultCCompiler = "gcc"
+  defaultCppCompiler = "g++"
+
 var
   gDoneRecursive: seq[string] = @[]
   gDoneInline: seq[string] = @[]
@@ -8,6 +14,8 @@ var
   gConfig: Config
   gFilter = ""
   gQuotes = true
+  gCppCompiler = getEnv(cppCompilerEnv, defaultCCompiler)
+  gCCompiler = getEnv(cCompilerEnv, defaultCppCompiler)
   gOutput = ""
   gIncludes: seq[string] = @[]
   gExcludes: seq[string] = @[]
@@ -33,6 +41,33 @@ Options:
 # ###
 # Helpers
 
+proc addEnv(str: string): string =
+  var newStr = str
+  for pair in envPairs():
+    try:
+      newStr = newStr % [pair.key, pair.value.string]
+    except ValueError:
+      # Ignore if there are no values to replace. We
+      # want to continue anyway
+      discard
+
+  try:
+    newStr = newStr % ["output", gOutput]
+  except ValueError:
+    # Ignore if there are no values to replace. We
+    # want to continue anyway
+    discard
+
+  # if there are still format args, print a warning
+  if newStr.contains("${"):
+    echo "WARNING: \"", newStr, "\" still contains an uninterpolated value!"
+
+  return newStr
+
+proc `[]`(table: OrderedTableRef[string, string], key: string): string =
+  ## Gets table values with env vars inserted
+  tables.`[]`(table, key).addEnv
+
 proc execProc(cmd: string): string =
   result = ""
   var
@@ -379,7 +414,7 @@ proc getDefines(file: string, inline=false): string =
 
 proc runPreprocess(file, ppflags, flags: string, inline: bool): string =
   var
-    pproc = if flags.contains("cpp"): "g++" else: "gcc"
+    pproc = if flags.contains("cpp"): gCppCompiler else: gCCompiler
     cmd = "$# -E $# $#" % [pproc, ppflags, file]
 
   for inc in gIncludes:
@@ -612,7 +647,9 @@ proc runFile(file: string, cfgin: OrderedTableRef) =
       if action == "create":
         createDir(file.splitPath().head)
         writeFile(file, cfg[act])
-      elif action in @["prepend", "append", "replace", "comment", "rename", "compile", "dynlib", "pragma", "pipe"] and sfile != "":
+      elif action in @["prepend", "append", "replace", "comment",
+                       "rename", "compile", "dynlib", "pragma",
+                       "pipe"] and sfile != "":
         if action == "prepend":
           if srch != "":
             prepend(sfile, cfg[act], cfg[srch])
@@ -702,6 +739,18 @@ proc runCfg(cfg: string) =
               quit(1)
       createDir(gOutput)
 
+    if gConfig["n.global"].hasKey("cpp_compiler"):
+      gCppCompiler = gConfig["n.global"]["cpp_compiler"]
+    else:
+      # Reset on a per project basis
+      gCppCompiler = getEnv(cppCompilerEnv, defaultCppCompiler)
+
+    if gConfig["n.global"].hasKey("c_compiler"):
+      gCCompiler = gConfig["n.global"]["c_compiler"]
+    else:
+      # Reset on a per project basis
+      gCCompiler = getEnv(cCompilerEnv, defaultCCompiler)
+
     if gConfig["n.global"].hasKey("filter"):
       gFilter = gConfig["n.global"]["filter"]
     if gConfig["n.global"].hasKey("quotes"):
@@ -710,30 +759,31 @@ proc runCfg(cfg: string) =
 
   if gConfig.hasKey("n.include"):
     for inc in gConfig["n.include"].keys():
-      gIncludes.add(inc)
+      gIncludes.add(inc.addEnv())
 
   if gConfig.hasKey("n.exclude"):
     for excl in gConfig["n.exclude"].keys():
-      gExcludes.add(excl)
+      gExcludes.add(excl.addEnv())
 
   if gConfig.hasKey("n.prepare"):
     for prep in gConfig["n.prepare"].keys():
       let (key, val) = getKey(prep)
       if val == true:
+        let prepVal = gConfig["n.prepare"][prep]
         if key == "download":
-          downloadUrl(gConfig["n.prepare"][prep])
+          downloadUrl(prepVal)
         elif key == "extract":
-          extractZip(gConfig["n.prepare"][prep])
+          extractZip(prepVal)
         elif key == "git":
-          gitRemotePull(gConfig["n.prepare"][prep])
+          gitRemotePull(prepVal)
         elif key == "gitremote":
-          gitRemotePull(gConfig["n.prepare"][prep], false)
+          gitRemotePull(prepVal, false)
         elif key == "gitsparse":
-          gitSparseCheckout(gConfig["n.prepare"][prep])
+          gitSparseCheckout(prepVal)
         elif key == "execute":
-          discard execProc(gConfig["n.prepare"][prep])
+          discard execProc(prepVal)
         elif key == "copy":
-          doCopy(gConfig["n.prepare"][prep])
+          doCopy(prepVal)
 
   if gConfig.hasKey("n.wildcard"):
     var wildcard = ""
@@ -743,7 +793,8 @@ proc runCfg(cfg: string) =
         if key == "wildcard":
           wildcard = gConfig["n.wildcard"][wild]
         else:
-          gWildcards.setSectionKey(wildcard, wild, gConfig["n.wildcard"][wild])
+          gWildcards.setSectionKey(wildcard, wild,
+                                   gConfig["n.wildcard"][wild])
 
   for file in gConfig.keys():
     if file in @["n.global", "n.include", "n.exclude", "n.prepare", "n.wildcard"]: