Nimscript: added support for 'patchFile'

compiler/options.nim

@@ -151,6 +151,7 @@ const
 var
   gConfigVars* = newStringTable(modeStyleInsensitive)
   gDllOverrides = newStringTable(modeCaseInsensitive)
+  gModuleOverrides* = newStringTable(modeStyleInsensitive)
   gPrefixDir* = "" # Overrides the default prefix dir in getPrefixDir proc.
   libpath* = ""
   gProjectName* = "" # holds a name like 'nim'
@@ -374,6 +375,13 @@ proc rawFindFile2(f: string): string =
     it = PStrEntry(it.next)
   result = ""
 
+template patchModule() {.dirty.} =
+  if result.len > 0 and gModuleOverrides.len > 0:
+    let key = getPackageName(result) & "_" & splitFile(result).name
+    if gModuleOverrides.hasKey(key):
+      let ov = gModuleOverrides[key]
+      if ov.len > 0: result = ov
+
 proc findFile*(f: string): string {.procvar.} =
   if f.isAbsolute:
     result = if f.existsFile: f else: ""
@@ -385,6 +393,7 @@ proc findFile*(f: string): string {.procvar.} =
         result = f.rawFindFile2
         if result.len == 0:
           result = f.toLower.rawFindFile2
+  patchModule()
 
 proc findModule*(modulename, currentModule: string): string =
   # returns path to module
@@ -403,6 +412,7 @@ proc findModule*(modulename, currentModule: string): string =
   result = currentPath / m
   if not existsFile(result):
     result = findFile(m)
+  patchModule()
 
 proc libCandidates*(s: string, dest: var seq[string]) =
   var le = strutils.find(s, '(')

compiler/scriptconfig.nim

@@ -13,7 +13,7 @@
 import
   ast, modules, passes, passaux, condsyms,
   options, nimconf, lists, sem, semdata, llstream, vm, vmdef, commands, msgs,
-  os, times, osproc, wordrecg
+  os, times, osproc, wordrecg, strtabs
 
 # we support 'cmpIgnoreStyle' natively for efficiency:
 from strutils import cmpIgnoreStyle
@@ -122,6 +122,12 @@ proc setupVM*(module: PSym; scriptName: string): PEvalContext =
   cbconf warningImpl:
     processSpecificNote(a.getString 0, wWarning, passPP, unknownLineInfo(),
       a.getString 1)
+  cbconf patchFile:
+    let key = a.getString(0) & "_" & a.getString(1)
+    var val = a.getString(2).addFileExt(NimExt)
+    if not isAbsolute(val):
+      val = vthisDir / val
+    gModuleOverrides[key] = val
 
 proc runNimScript*(scriptName: string; freshDefines=true) =
   passes.gIncludeFile = includeModule

lib/system/nimscript.nim

@@ -65,6 +65,21 @@ proc hint*(name: string; val: bool) =
   let v = if val: "on" else: "off"
   hintImpl(name & "]:" & v, "hint[" & name & "]:" & v)
 
+proc patchFile*(package, filename, replacement: string) =
+  ## Overrides the location of a given file belonging to the
+  ## passed package.
+  ## If the ``replacement`` is not an absolute path, the path
+  ## is interpreted to be local to the Nimscript file that contains
+  ## the call to ``patchFile``, Nim's ``--path`` is not used at all
+  ## to resolve the filename!
+  ##
+  ## Example:
+  ##
+  ## .. code-block:: nim
+  ##
+  ##   patchFile("stdlib", "asyncdispatch", "patches/replacement")
+  discard
+
 proc getCommand*(): string =
   ## Gets the Nim command that the compiler has been invoked with, for example
   ## "c", "js", "build", "help".

tests/newconfig/mymath.nim

@@ -0,0 +1,4 @@
+
+
+proc ln*(x: float): float =
+  return 0.5

tests/newconfig/tfoo.nim

@@ -1,10 +1,12 @@
 discard """
   cmd: "nim default $file"
-  output: '''hello world!'''
+  output: '''hello world! 0.5'''
   msg: '''[NimScript] exec: gcc -v'''
 """
 
 when not defined(definedefine):
   {.fatal: "wrong nim script configuration".}
 
-echo "hello world!"
+import math
+
+echo "hello world! ", ln 2.0

tests/newconfig/tfoo.nims

@@ -11,6 +11,8 @@ import ospaths
 warning("uninit", off)
 hint("processing", off)
 
+patchFile("stdlib", "math", "mymath")
+
 task listDirs, "lists every subdirectory":
   for x in listDirs("."):
     echo "DIR ", x

web/news/version_0_15_released.rst

@@ -49,6 +49,16 @@ Compiler Additions
 - The ``-d/--define`` flag can now optionally take a value to be used
   by code at compile time.
 
+Nimscript Additions
+-------------------
+
+- Finally it's possible to dis/enable specific hints and warnings in
+  Nimscript via the procs ``warning`` and ``hint``.
+- Nimscript exports  a proc named ``patchFile`` which can be used to
+  patch modules or include files for different Nimble packages, including
+  the ``stdlib`` package.
+
+
 Language Additions
 ------------------