new compiler feature: --expandMacro

4 files changed, 12 insertions, 4 deletions

diff --git a/compiler/commands.nim b/compiler/commands.nim
index 298fbdc89..cf7fef24d 100644
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -27,7 +27,7 @@ bootSwitch(usedNoGC, defined(nogc), "--gc:none")
 import
   os, msgs, options, nversion, condsyms, strutils, extccomp, platform,
   wordrecg, parseutils, nimblecmd, idents, parseopt, sequtils, lineinfos,
-  pathutils
+  pathutils, strtabs
 
 # but some have deps to imported modules. Yay.
 bootSwitch(usedTinyC, hasTinyCBackend, "-d:tinyc")
@@ -774,6 +774,9 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
     processOnOffSwitchG(conf, {optDocInternal}, arg, pass, info)
   of "multimethods":
     processOnOffSwitchG(conf, {optMultiMethods}, arg, pass, info)
+  of "expandmacro":
+    expectArg(conf, switch, arg, pass, info)
+    conf.macrosToExpand[arg] = "T"
   of "":
     conf.projectName = "-"
   else:
diff --git a/compiler/lineinfos.nim b/compiler/lineinfos.nim
index 908c5f5ed..b84d8c895 100644
--- a/compiler/lineinfos.nim
+++ b/compiler/lineinfos.nim
@@ -44,7 +44,7 @@ type
     hintConditionAlwaysTrue, hintConditionAlwaysFalse, hintName, hintPattern,
     hintExecuting, hintLinking, hintDependency,
     hintSource, hintPerformance, hintStackTrace, hintGCStats,
-    hintGlobalVar,
+    hintGlobalVar, hintExpandMacro,
     hintUser, hintUserRaw,
     hintExtendedContext
 
@@ -117,6 +117,7 @@ const
     hintStackTrace: "$1",
     hintGCStats: "$1",
     hintGlobalVar: "global variable declared here",
+    hintExpandMacro: "expanded macro: $1",
     hintUser: "$1",
     hintUserRaw: "$1",
     hintExtendedContext: "$1",
@@ -141,7 +142,7 @@ const
     "XDeclaredButNotUsed", "ConvToBaseNotNeeded", "ConvFromXtoItselfNotNeeded",
     "ExprAlwaysX", "QuitCalled", "Processing", "CodeBegin", "CodeEnd", "Conf",
     "Path", "CondTrue", "CondFalse", "Name", "Pattern", "Exec", "Link", "Dependency",
-    "Source", "Performance", "StackTrace", "GCStats", "GlobalVar",
+    "Source", "Performance", "StackTrace", "GCStats", "GlobalVar", "ExpandMacro",
     "User", "UserRaw", "ExtendedContext",
   ]
 
diff --git a/compiler/options.nim b/compiler/options.nim
index bacef5b4a..833af6846 100644
--- a/compiler/options.nim
+++ b/compiler/options.nim
@@ -180,6 +180,7 @@ type
     linesCompiled*: int  # all lines that have been compiled
     options*: TOptions    # (+)
     globalOptions*: TGlobalOptions # (+)
+    macrosToExpand*: StringTableRef
     m*: MsgConfig
     evalTemplateCounter*: int
     evalMacroCounter*: int
@@ -308,6 +309,7 @@ proc newConfigRef*(): ConfigRef =
     verbosity: 1,
     options: DefaultOptions,
     globalOptions: DefaultGlobalOptions,
+    macrosToExpand: newStringTable(modeStyleInsensitive),
     m: initMsgConfig(),
     evalExpr: "",
     cppDefines: initSet[string](),
diff --git a/compiler/sem.nim b/compiler/sem.nim
index a4e6a427b..3c5d036dc 100644
--- a/compiler/sem.nim
+++ b/compiler/sem.nim
@@ -16,7 +16,7 @@ import
   procfind, lookups, pragmas, passes, semdata, semtypinst, sigmatch,
   intsets, transf, vmdef, vm, idgen, aliases, cgmeth, lambdalifting,
   evaltempl, patterns, parampatterns, sempass2, linter, semmacrosanity,
-  lowerings, pluginsupport, plugins/active, rod, lineinfos
+  lowerings, pluginsupport, plugins/active, rod, lineinfos, strtabs
 
 from modulegraphs import ModuleGraph, PPassContext, onUse, onDef, onDefResolveForward
 
@@ -467,6 +467,8 @@ proc semMacroExpr(c: PContext, n, nOrig: PNode, sym: PSym,
   result = evalMacroCall(c.module, c.graph, n, nOrig, sym)
   if efNoSemCheck notin flags:
     result = semAfterMacroCall(c, n, result, sym, flags)
+  if c.config.macrosToExpand.hasKey(sym.name.s):
+    message(c.config, nOrig.info, hintExpandMacro, renderTree(result))
   result = wrapInComesFrom(nOrig.info, sym, result)
   popInfoContext(c.config)