Merge pull request #58 from zah/getast-unittests

getAst operational. Unit testing library based on it.

compiler/ast.nim

@@ -327,7 +327,7 @@ type
   TMagic* = enum # symbols that require compiler magic:
     mNone, mDefined, mDefinedInScope, mLow, mHigh, mSizeOf, mIs, mOf,
     mEcho, mShallowCopy, mSlurp,
-    mAstToYaml, mParseExprToAst, mParseStmtToAst, mExpandMacroToAst,
+    mAstToYaml, mParseExprToAst, mParseStmtToAst, mExpandToAst,
     mUnaryLt, mSucc, 
     mPred, mInc, mDec, mOrd, mNew, mNewFinalize, mNewSeq, mLengthOpenArray, 
     mLengthStr, mLengthArray, mLengthSeq, mIncl, mExcl, mCard, mChr, mGCref, 
@@ -369,7 +369,7 @@ type
     mCompileOption, mCompileOptionArg,
     mNLen, mNChild, mNSetChild, mNAdd, mNAddMultiple, mNDel, mNKind, 
     mNIntVal, mNFloatVal, mNSymbol, mNIdent, mNGetType, mNStrVal, mNSetIntVal, 
-    mNSetFloatVal, mNSetSymbol, mNSetIdent, mNSetType, mNSetStrVal, 
+    mNSetFloatVal, mNSetSymbol, mNSetIdent, mNSetType, mNSetStrVal, mNLineInfo,
     mNNewNimNode, mNCopyNimNode, mNCopyNimTree, mStrToIdent, mIdentToStr, 
     mEqIdent, mEqNimrodNode, mNHint, mNWarning, mNError, mGetTypeInfo
 

compiler/evals.nim

@@ -65,6 +65,7 @@ proc popStackFrame*(c: PEvalContext) {.inline.} =
   if (c.tos == nil): InternalError("popStackFrame")
   c.tos = c.tos.next
 
+proc eval*(c: PEvalContext, n: PNode): PNode
 proc evalAux(c: PEvalContext, n: PNode, flags: TEvalFlags): PNode
 
 proc stackTraceAux(x: PStackFrame) =
@@ -764,7 +765,7 @@ proc isEmpty(n: PNode): bool =
 proc stringStartingLine(s: PNode): int =
   result = s.info.line - countLines(s.strVal)
 
-proc evalParseExpr(c: PEvalContext, n: Pnode): Pnode =
+proc evalParseExpr(c: PEvalContext, n: PNode): PNode =
   var code = evalAux(c, n.sons[1], {})
   var ast = parseString(code.getStrValue, code.info.toFilename,
                         code.stringStartingLine)
@@ -773,12 +774,108 @@ proc evalParseExpr(c: PEvalContext, n: Pnode): Pnode =
   result = ast.sons[0]
   result.typ = newType(tyExpr, c.module)
 
-proc evalParseStmt(c: PEvalContext, n: Pnode): Pnode =
+proc evalParseStmt(c: PEvalContext, n: PNode): PNode =
   var code = evalAux(c, n.sons[1], {})
   result = parseString(code.getStrValue, code.info.toFilename,
                        code.stringStartingLine)
   result.typ = newType(tyStmt, c.module)
 
+proc evalTemplateAux*(templ, actual: PNode, sym: PSym): PNode = 
+  case templ.kind
+  of nkSym: 
+    var p = templ.sym
+    if (p.kind == skParam) and (p.owner.id == sym.id): 
+      result = copyTree(actual.sons[p.position])
+    else: 
+      result = copyNode(templ)
+  of nkNone..nkIdent, nkType..nkNilLit: # atom
+    result = copyNode(templ)
+  else: 
+    result = copyNode(templ)
+    newSons(result, sonsLen(templ))
+    for i in countup(0, sonsLen(templ) - 1): 
+      result.sons[i] = evalTemplateAux(templ.sons[i], actual, sym)
+
+proc evalTemplateArgs(n: PNode, s: PSym): PNode =
+  var 
+    f, a: int
+    arg: PNode
+    
+  f = sonsLen(s.typ)
+
+  # if the template has zero arguments, it can be called without ``()``
+  # `n` is then a nkSym or something similar
+  case n.kind
+  of nkCall, nkInfix, nkPrefix, nkPostfix, nkCommand, nkCallStrLit:
+    a = sonsLen(n)
+  else: a = 0
+  
+  if a > f: GlobalError(n.info, errWrongNumberOfArguments)
+
+  result = copyNode(n)
+  for i in countup(1, f - 1):
+    if i < a:
+      arg = n.sons[i]
+    else:
+      arg = copyTree(s.typ.n.sons[i].sym.ast)
+
+    addSon(result, arg)
+
+var evalTemplateCounter = 0
+  # to prevend endless recursion in templates instantation
+
+proc evalTemplate(n: PNode, sym: PSym): PNode = 
+  inc(evalTemplateCounter)
+  if evalTemplateCounter > 100:
+    GlobalError(n.info, errTemplateInstantiationTooNested)
+
+  # replace each param by the corresponding node:
+  var args = evalTemplateArgs(n, sym)
+  result = evalTemplateAux(sym.ast.sons[codePos], args, sym)
+
+  dec(evalTemplateCounter)
+
+proc evalMacroCall*(c: PEvalContext, n: PNode, sym: PSym): PNode =
+  inc(evalTemplateCounter)
+  if evalTemplateCounter > 100: 
+    GlobalError(n.info, errTemplateInstantiationTooNested)
+
+  var s = newStackFrame()
+  s.call = n
+  setlen(s.params, 2)
+  s.params[0] = newNodeIT(nkNilLit, n.info, sym.typ.sons[0])
+  s.params[1] = n
+  pushStackFrame(c, s)
+  discard eval(c, sym.ast.sons[codePos])
+  result = s.params[0]
+  popStackFrame(c)
+  if cyclicTree(result): GlobalError(n.info, errCyclicTree)
+
+  dec(evalTemplateCounter)
+  
+proc evalExpandToAst(c: PEvalContext, original: PNode): PNode =
+  var
+    n = original.copyTree
+    macroCall = n.sons[1]
+    expandedSym = macroCall.sons[0].sym
+
+  for i in countup(1, macroCall.sonsLen - 1):
+    macroCall.sons[i] = evalAux(c, macroCall.sons[i], {})
+
+  case expandedSym.kind
+  of skTemplate:
+    result = evalTemplate(macroCall, expandedSym)
+  of skMacro:
+    # At this point macroCall.sons[0] is nkSym node.
+    # To be completely compatible with normal macro invocation,
+    # we want to replace it with nkIdent node featuring
+    # the original unmangled macro name.
+    macroCall.sons[0] = newIdentNode(expandedSym.name, expandedSym.info)
+    result = evalMacroCall(c, macroCall, expandedSym)
+  else:
+    InternalError(macroCall.info,
+      "ExpandToAst: expanded symbol is no macro or template")
+
 proc evalMagicOrCall(c: PEvalContext, n: PNode): PNode = 
   var m = getMagic(n)
   case m
@@ -805,6 +902,7 @@ proc evalMagicOrCall(c: PEvalContext, n: PNode): PNode =
   of mAppendSeqElem: result = evalAppendSeqElem(c, n)
   of mParseExprToAst: result = evalParseExpr(c, n)
   of mParseStmtToAst: result = evalParseStmt(c, n)
+  of mExpandToAst: result = evalExpandToAst(c, n)
   of mNLen:
     result = evalAux(c, n.sons[1], {efLValue})
     if isSpecial(result): return 
@@ -1011,6 +1109,10 @@ proc evalMagicOrCall(c: PEvalContext, n: PNode): PNode =
     if (a == b) or
         (b.kind in {nkNilLit, nkEmpty}) and (a.kind in {nkNilLit, nkEmpty}): 
       result.intVal = 1
+  of mNLineInfo:
+    result = evalAux(c, n.sons[1], {})
+    if isSpecial(result): return
+    result = newStrNodeT(result.info.toFileLineCol, n)
   of mAstToYaml:
     var ast = evalAux(c, n.sons[1], {efLValue})
     result = newStrNode(nkStrLit, ast.treeToYaml.ropeToStr)

compiler/msgs.nim

@@ -456,6 +456,12 @@ proc ToLinenumber*(info: TLineInfo): int {.inline.} =
 proc toColumn*(info: TLineInfo): int {.inline.} = 
   result = info.col
 
+proc toFileLine*(info: TLineInfo): string {.inline.} =
+  result = info.toFilename & ":" & $info.line
+
+proc toFileLineCol*(info: TLineInfo): string {.inline.} =
+  result = info.toFilename & "(" & $info.line & "," & $info.col & ")"
+
 var checkPoints: seq[TLineInfo] = @[]
 
 proc addCheckpoint*(info: TLineInfo) = 

compiler/sem.nim

@@ -12,27 +12,13 @@
 import
   strutils, hashes, lists, options, lexer, ast, astalgo, trees, treetab,
   wordrecg, ropes, msgs, os, condsyms, idents, renderer, types, platform, math,
-  magicsys, parser, nversion, nimsets, semdata, evals, semfold, importer, 
+  magicsys, parser, nversion, semdata, nimsets, semfold, importer,
   procfind, lookups, rodread, pragmas, passes, semtypinst, sigmatch, suggest,
-  semthreads, intsets, transf
+  semthreads, intsets, transf, evals
 
 proc semPass*(): TPass
 # implementation
 
-proc isTopLevel(c: PContext): bool {.inline.} = 
-  result = c.tab.tos <= 2
-
-proc newSymS(kind: TSymKind, n: PNode, c: PContext): PSym = 
-  result = newSym(kind, considerAcc(n), getCurrOwner())
-  result.info = n.info
-  
-proc semIdentVis(c: PContext, kind: TSymKind, n: PNode,
-                 allowed: TSymFlags): PSym
-  # identifier with visability
-proc semIdentWithPragma(c: PContext, kind: TSymKind, n: PNode, 
-                        allowed: TSymFlags): PSym
-proc semStmtScope(c: PContext, n: PNode): PNode
-
 type 
   TExprFlag = enum 
     efAllowType, efLValue, efWantIterator, efInTypeof
@@ -50,10 +36,36 @@ proc addResult(c: PContext, t: PType, info: TLineInfo)
 proc addResultNode(c: PContext, n: PNode)
 proc instGenericContainer(c: PContext, n: PNode, header: PType): PType
 
+proc typeMismatch(n: PNode, formal, actual: PType) = 
+  GlobalError(n.Info, errGenerated, msgKindToString(errTypeMismatch) &
+      typeToString(actual) & ") " &
+      `%`(msgKindToString(errButExpectedX), [typeToString(formal)]))
+
+proc fitNode(c: PContext, formal: PType, arg: PNode): PNode = 
+  result = IndexTypesMatch(c, formal, arg.typ, arg)
+  if result == nil:
+    typeMismatch(arg, formal, arg.typ)
+
+proc isTopLevel(c: PContext): bool {.inline.} = 
+  result = c.tab.tos <= 2
+
+proc newSymS(kind: TSymKind, n: PNode, c: PContext): PSym = 
+  result = newSym(kind, considerAcc(n), getCurrOwner())
+  result.info = n.info
+  
+proc semIdentVis(c: PContext, kind: TSymKind, n: PNode,
+                 allowed: TSymFlags): PSym
+  # identifier with visability
+proc semIdentWithPragma(c: PContext, kind: TSymKind, n: PNode, 
+                        allowed: TSymFlags): PSym
+proc semStmtScope(c: PContext, n: PNode): PNode
+
 proc ParamsTypeCheck(c: PContext, typ: PType) {.inline.} =
   if not typeAllowed(typ, skConst):
     GlobalError(typ.n.info, errXisNoType, typeToString(typ))
 
+include semtempl
+
 proc semConstExpr(c: PContext, n: PNode): PNode = 
   var e = semExprWithType(c, n)
   if e == nil: 
@@ -77,16 +89,6 @@ proc semAndEvalConstExpr(c: PContext, n: PNode): PNode =
   
 include seminst, semcall
     
-proc typeMismatch(n: PNode, formal, actual: PType) = 
-  GlobalError(n.Info, errGenerated, msgKindToString(errTypeMismatch) &
-      typeToString(actual) & ") " &
-      `%`(msgKindToString(errButExpectedX), [typeToString(formal)]))
-
-proc fitNode(c: PContext, formal: PType, arg: PNode): PNode = 
-  result = IndexTypesMatch(c, formal, arg.typ, arg)
-  if result == nil:
-    typeMismatch(arg, formal, arg.typ)
-  
 proc semAfterMacroCall(c: PContext, n: PNode, s: PSym): PNode = 
   result = n
   case s.typ.sons[0].kind
@@ -102,27 +104,12 @@ proc semAfterMacroCall(c: PContext, n: PNode, s: PSym): PNode =
     result = fitNode(c, s.typ.sons[0], result)
     #GlobalError(s.info, errInvalidParamKindX, typeToString(s.typ.sons[0]))
 
-include "semtempl.nim"
-
 proc semMacroExpr(c: PContext, n: PNode, sym: PSym, 
                   semCheck: bool = true): PNode = 
-  inc(evalTemplateCounter)
-  if evalTemplateCounter > 100: 
-    GlobalError(n.info, errTemplateInstantiationTooNested)
   markUsed(n, sym)
   var p = newEvalContext(c.module, "", false)
-  var s = newStackFrame()
+  result = evalMacroCall(p, n, sym)
-  s.call = n
-  setlen(s.params, 2)
-  s.params[0] = newNodeIT(nkNilLit, n.info, sym.typ.sons[0])
-  s.params[1] = n
-  pushStackFrame(p, s)
-  discard eval(p, sym.ast.sons[codePos])
-  result = s.params[0]
-  popStackFrame(p)
-  if cyclicTree(result): GlobalError(n.info, errCyclicTree)
   if semCheck: result = semAfterMacroCall(c, result, sym)
-  dec(evalTemplateCounter)
 
 proc forceBool(c: PContext, n: PNode): PNode = 
   result = fitNode(c, getSysType(tyBool), n)

compiler/semexprs.nim

@@ -904,26 +904,37 @@ proc expectStringArg(c: PContext, n: PNode, i: int): PNode =
   if result.kind notin {nkStrLit, nkRStrLit, nkTripleStrLit}:
     GlobalError(result.info, errStringLiteralExpected)
 
-proc semExpandMacroToAst(c: PContext, n: PNode, flags: TExprFlags): PNode =
+proc isAstValue(n: PNode): bool =
+  result = n.typ.sym.name.s in [ "expr", "stmt", "PNimrodNode" ]
+
+proc semExpandToAst(c: PContext, n: PNode, magicSym: PSym, flags: TExprFlags): PNode =
   if sonsLen(n) == 2:
     if not isCallExpr(n.sons[1]):
       GlobalError(n.info, errXisNoMacroOrTemplate, n.renderTree)
 
     var macroCall = n.sons[1]
 
-    var s = qualifiedLookup(c, macroCall.sons[0], {checkUndeclared})
+    var expandedSym = qualifiedLookup(c, macroCall.sons[0], {checkUndeclared})
-    if s == nil:
+    if expandedSym == nil:
       GlobalError(n.info, errUndeclaredIdentifier, macroCall.sons[0].renderTree)
 
-    var expanded : Pnode
+    if not (expandedSym.kind in { skMacro, skTemplate }):
+      GlobalError(n.info, errXisNoMacroOrTemplate, expandedSym.name.s)
 
-    case s.kind
+    macroCall.sons[0] = newNodeI(nkSym, macroCall.info)
-    of skMacro: expanded = semMacroExpr(c, macroCall, s, false)
+    macroCall.sons[0].sym = expandedSym
-    of skTemplate: expanded = semTemplateExpr(c, macroCall, s, false)
+    markUsed(n, expandedSym)
-    else: GlobalError(n.info, errXisNoMacroOrTemplate, s.name.s)
 
-    var macroRetType = newTypeS(s.typ.sons[0].kind, c)
+    for i in countup(1, macroCall.sonsLen - 1):
-    result = newMetaNodeIT(expanded, n.info, macroRetType)
+      macroCall.sons[i] = semExprWithType(c, macroCall.sons[i], {efAllowType})
+
+    # Preserve the magic symbol in order to handled in evals.nim
+    n.sons[0] = newNodeI(nkSym, n.info)
+    n.sons[0].sym = magicSym
+   
+    n.typ = expandedSym.getReturnType
+
+    result = n
   else:
     result = semDirectOp(c, n, flags)
 
@@ -963,7 +974,7 @@ proc semMagic(c: PContext, n: PNode, s: PSym, flags: TExprFlags): PNode =
     else:
       result = semDirectOp(c, n, flags)
   of mSlurp: result = semSlurp(c, n, flags)
-  of mExpandMacroToAst: result = semExpandMacroToAst(c, n, flags)
+  of mExpandToAst: result = semExpandToAst(c, n, s, flags)
   else: result = semDirectOp(c, n, flags)
 
 proc semIfExpr(c: PContext, n: PNode): PNode = 

compiler/semfold.nim

@@ -206,7 +206,7 @@ proc evalOp(m: TMagic, n, a, b, c: PNode): PNode =
   of mNewString, mNewStringOfCap, 
      mExit, mInc, ast.mDec, mEcho, mAssert, mSwap, mAppendStrCh, 
      mAppendStrStr, mAppendSeqElem, mSetLengthStr, mSetLengthSeq, 
-     mParseExprToAst, mParseStmtToAst,
+     mParseExprToAst, mParseStmtToAst, mExpandToAst,
      mNLen..mNError, mEqRef: 
     nil
   else: InternalError(a.info, "evalOp(" & $m & ')')

compiler/semstmts.nim

@@ -439,6 +439,10 @@ proc semTry(c: PContext, n: PNode): PNode =
     checkMinSonsLen(a, 1)
     var length = sonsLen(a)
     if a.kind == nkExceptBranch:
+      if length == 2 and a.sons[0].kind == nkBracket:
+        a.sons[0..0] = a.sons[0].sons
+        length = a.sonsLen
+
       for j in countup(0, length - 2):
         var typ = semTypeNode(c, a.sons[j], nil)
         if typ.kind == tyRef: typ = typ.sons[0]

compiler/semtempl.nim

@@ -33,22 +33,6 @@ proc isTypeDesc(n: PNode): bool =
     result = true
   else: result = false
   
-proc evalTemplateAux(c: PContext, templ, actual: PNode, sym: PSym): PNode = 
-  case templ.kind
-  of nkSym: 
-    var p = templ.sym
-    if (p.kind == skParam) and (p.owner.id == sym.id): 
-      result = copyTree(actual.sons[p.position])
-    else: 
-      result = copyNode(templ)
-  of nkNone..nkIdent, nkType..nkNilLit: # atom
-    result = copyNode(templ)
-  else: 
-    result = copyNode(templ)
-    newSons(result, sonsLen(templ))
-    for i in countup(0, sonsLen(templ) - 1): 
-      result.sons[i] = evalTemplateAux(c, templ.sons[i], actual, sym)
-  
 var evalTemplateCounter: int = 0
   # to prevend endless recursion in templates instantation
 
@@ -77,13 +61,13 @@ proc evalTemplateArgs(c: PContext, n: PNode, s: PSym): PNode =
       arg = fitNode(c, s.typ.sons[i], semExprWithType(c, arg))
     addSon(result, arg)
 
-proc evalTemplate(c: PContext, n: PNode, sym: PSym): PNode = 
+proc evalTemplate*(c: PContext, n: PNode, sym: PSym): PNode = 
   var args: PNode
   inc(evalTemplateCounter)
   if evalTemplateCounter <= 100: 
     # replace each param by the corresponding node:
     args = evalTemplateArgs(c, n, sym)
-    result = evalTemplateAux(c, sym.ast.sons[codePos], args, sym)
+    result = evalTemplateAux(sym.ast.sons[codePos], args, sym)
     dec(evalTemplateCounter)
   else:
     GlobalError(n.info, errTemplateInstantiationTooNested)

compiler/types.nim

@@ -925,6 +925,11 @@ proc computeSize(typ: PType): biggestInt =
   var a: biggestInt = 1
   result = computeSizeAux(typ, a)
 
+proc getReturnType*(s: PSym): PType =
+  # Obtains the return type of a iterator/proc/macro/template
+  assert s.kind in { skProc, skTemplate, skMacro, skIterator }
+  result = s.typ.n.sons[0].typ
+
 proc getSize(typ: PType): biggestInt = 
   result = computeSize(typ)
   if result < 0: InternalError("getSize(" & $typ.kind & ')')

lib/core/macros.nim

@@ -187,6 +187,8 @@ proc toStrLit*(n: PNimrodNode): PNimrodNode {.compileTime.} =
   ## in a string literal node
   return newStrLitNode(repr(n))
 
+proc lineinfo*(n: PNimrodNode): string {.magic: "NLineInfo".}
+
 proc toLisp*(n: PNimrodNode): string {.compileTime.} =
   ## Convert the AST `n` to a human-readable string
   ##
@@ -228,7 +230,7 @@ proc parseStmt*(s: string): stmt {.magic: "ParseStmtToAst".}
   ## Compiles the passed string to its AST representation.
   ## Expects one or more statements.
 
-proc getAst*(macroOrTemplate: expr): expr {.magic: "ExpandMacroToAst".}
+proc getAst*(macroOrTemplate: expr): expr {.magic: "ExpandToAst".}
   ## Obtains the AST nodes returned from a macro or template invocation.
   ## Example:
   ## 

lib/pure/terminal.nim

@@ -14,6 +14,8 @@
 ## Changing the style is permanent even after program termination! Use the
 ## code ``system.addQuitProc(resetAttributes)`` to restore the defaults.
 
+import macros
+
 when defined(windows):
   import windows, os
 
@@ -210,24 +212,32 @@ type
 
 when not defined(windows):
   var
+    # XXX: These better be thread-local
     gFG = 0
     gBG = 0
 
-proc WriteStyled*(txt: string, style: set[TStyle] = {styleBright}) =
+proc setStyle*(style: set[TStyle]) =
-  ## writes the text `txt` in a given `style`.
+  ## sets the terminal style
   when defined(windows):
     var a = 0'i16
     if styleBright in style: a = a or int16(FOREGROUND_INTENSITY)
     if styleBlink in style: a = a or int16(BACKGROUND_INTENSITY)
     if styleReverse in style: a = a or 0x4000'i16 # COMMON_LVB_REVERSE_VIDEO
     if styleUnderscore in style: a = a or 0x8000'i16 # COMMON_LVB_UNDERSCORE
-    var old = getAttributes()
     discard SetConsoleTextAttribute(conHandle, old or a)
-    stdout.write(txt)
-    discard SetConsoleTextAttribute(conHandle, old)
   else:
     for s in items(style):
       stdout.write("\e[" & $ord(s) & 'm')
+
+proc WriteStyled*(txt: string, style: set[TStyle] = {styleBright}) =
+  ## writes the text `txt` in a given `style`.
+  when defined(windows):
+    var old = getAttributes()
+    setStyle(style)
+    stdout.write(txt)
+    discard SetConsoleTextAttribute(conHandle, old)
+  else:
+    setStyle(style)
     stdout.write(txt)
     resetAttributes()
     if gFG != 0:
@@ -298,6 +308,24 @@ proc setBackgroundColor*(bg: TBackgroundColor, bright=false) =
     if bright: inc(gBG, 60)
     stdout.write("\e[" & $gBG & 'm')
 
+# XXX: 
+# These should be private, but there is no yet 
+# facility for binding local symbols within macros
+proc styledEchoProcessArg*(s: string)               = write stdout, s
+proc styledEchoProcessArg*(style: TStyle)           = setStyle {style}
+proc styledEchoProcessArg*(style: set[TStyle])      = setStyle style
+proc styledEchoProcessArg*(color: TForegroundColor) = setForeGroundColor color
+proc styledEchoProcessArg*(color: TBackgroundColor) = setBackGroundColor color
+
+macro styledEcho*(m: stmt): stmt =
+  result = newNimNode(nnkStmtList)
+
+  for i in countup(1, m.len - 1):
+    result.add(newCall(!"styledEchoProcessArg", m[i]))
+
+  result.add(newCall(!"write", newIdentNode("stdout"), newStrLitNode("\n")))
+  result.add(newCall(!"resetAttributes"))
+
 when isMainModule:
   system.addQuitProc(resetAttributes)
   write(stdout, "never mind")

lib/pure/unittest.nim

@@ -0,0 +1,150 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2011 Nimrod Contributors
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements the standard unit testing facilities such as
+## suites, fixtures and test cases as well as facilities for combinatorial 
+## and randomzied test case generation (not yet available) 
+## and object mocking (not yet available)
+##
+## It is loosely based on C++'s boost.test and Haskell's QuickTest
+##
+## Maintainer: Zahary Karadjov (zah@github)
+##
+
+import
+  macros, terminal
+
+type
+  TestStatus* = enum OK, FAILED
+  # ETestFailed* = object of ESynch
+
+var 
+  # XXX: These better be thread-local
+  AbortOnError* = false
+  checkpoints: seq[string] = @[]
+
+template TestSetupIMPL*: stmt = nil
+template TestTeardownIMPL*: stmt = nil
+
+proc shouldRun(testName: string): bool =
+  result = true
+
+template suite*(name: expr, body: stmt): stmt =
+  block:
+    template setup(setupBody: stmt): stmt =
+      template TestSetupIMPL: stmt = setupBody
+
+    template teardown(teardownBody: stmt): stmt =
+      template TestTeardownIMPL: stmt = teardownBody
+
+    body
+
+proc printStatus*(s: TestStatus, name: string) =
+  var color = (if s == OK: fgGreen else: fgRed)
+  styledEcho styleBright, color, "[", $s, "] ", fgWhite, name, "\n"
+  
+template test*(name: expr, body: stmt): stmt =
+  if bind shouldRun(name):
+    bind checkpoints = @[]
+    var TestStatusIMPL = OK
+    
+    try:
+      TestSetupIMPL()
+      body
+
+    finally:
+      TestTeardownIMPL()
+      printStatus(TestStatusIMPL, name)
+
+proc checkpoint*(msg: string) =
+  checkpoints.add(msg)
+  # TODO: add support for something like SCOPED_TRACE from Google Test
+
+template fail* =
+  for msg in items(bind checkpoints):
+    echo msg
+
+  if AbortOnError: quit(1)
+  
+  TestStatusIMPL = FAILED
+  checkpoints = @[]
+
+macro check*(conditions: stmt): stmt =
+  proc standardRewrite(e: expr): stmt =
+    template rewrite(Exp, lineInfoLit: expr, expLit: string): stmt =
+      if not Exp:
+        checkpoint(lineInfoLit & ": Check failed: " & expLit)
+        fail()
+ 
+    result = getAst(rewrite(e, e.lineinfo, e.toStrLit))
+  
+  case conditions.kind
+  of nnkCall, nnkCommand, nnkMacroStmt:
+    case conditions[1].kind
+    of nnkInfix:
+      proc rewriteBinaryOp(op: expr): stmt =
+        template rewrite(op, left, right, lineInfoLit: expr, opLit, leftLit, rightLit: string): stmt =
+          block:
+            var 
+              lhs = left
+              rhs = right
+
+            if not `op`(lhs, rhs):
+              checkpoint(lineInfoLit & ": Check failed: " & opLit)
+              checkpoint("  " & leftLit & " was " & $lhs)
+              checkpoint("  " & rightLit & " was " & $rhs)
+              fail()
+
+        result = getAst(rewrite(
+          op[0], op[1], op[2],
+          op.lineinfo,
+          op.toStrLit,
+          op[1].toStrLit,
+          op[2].toStrLit))
+        
+      result = rewriteBinaryOp(conditions[1])
+  
+    of nnkCall, nnkCommand:
+      # TODO: We can print out the call arguments in case of failure
+      result = standardRewrite(conditions[1])
+
+    of nnkStmtList:
+      result = newNimNode(nnkStmtList)
+      for i in countup(0, conditions[1].len - 1):
+        result.add(newCall(!"check", conditions[1][i]))
+
+    else:
+      result = standardRewrite(conditions[1])
+
+  else:
+    error conditions.lineinfo & ": Malformed check statement"
+
+template require*(conditions: stmt): stmt =
+  block:
+    const AbortOnError = true    
+    check conditions
+
+macro expect*(exp: stmt): stmt =
+  template expectBody(errorTypes, lineInfoLit: expr, body: stmt): stmt =
+    try:
+      body
+      checkpoint(lineInfoLit & ": Expect Failed, no exception was thrown.")
+      fail()
+    except errorTypes:
+      nil
+
+  var expectCall = exp[0]
+  var body = exp[1]
+  
+  var errorTypes = newNimNode(nnkBracket)
+  for i in countup(1, expectCall.len - 1):
+    errorTypes.add(expectCall[i])
+
+  result = getAst(expectBody(errorTypes, exp.lineinfo, body))
+

lib/system.nim

@@ -857,7 +857,6 @@ proc insert*[T](x: var seq[T], item: T, i = 0) {.noSideEffect.} =
     dec(j)
   x[i] = item
 
-
 proc repr*[T](x: T): string {.magic: "Repr", noSideEffect.}
   ## takes any Nimrod variable and returns its string representation. It
   ## works even for complex data graphs with cycles. This is a great
@@ -1922,6 +1921,26 @@ proc `[]`*(s: string, x: TSlice[int]): string {.inline.} =
   ## slice operation for strings. Negative indexes are supported.
   result = s.substr(x.a-|s, x.b-|s)
 
+template spliceImpl(x, start, endp, spliced: expr): stmt =
+  var 
+    count = endp - start + 1
+    shift = spliced.len - count
+    newLen = x.len + shift
+    totalShifted = x.len - (start + count)
+    firstShifted = newLen - totalShifted
+
+  if shift > 0:
+    setLen(x, newLen)
+
+  for i in countdown(newLen - 1, firstShifted):
+    shallowCopy(x[i], x[i-shift])
+
+  for c in countup(0, spliced.len - 1):
+    x[start + c] = spliced[c]
+
+  if shift < 0:
+    setLen(x, newLen)
+
 proc `[]=`*(s: var string, x: TSlice[int], b: string) = 
   ## slice assignment for strings. Negative indexes are supported.
   var a = x.a-|s
@@ -1929,7 +1948,7 @@ proc `[]=`*(s: var string, x: TSlice[int], b: string) =
   if L == b.len:
     for i in 0 .. <L: s[i+a] = b[i]
   else:
-    raise newException(EOutOfRange, "differing lengths for slice assignment")
+    spliceImpl(s, x.a, x.b, b)
 
 proc `[]`*[Idx, T](a: array[Idx, T], x: TSlice[int]): seq[T] =
   ## slice operation for arrays. Negative indexes are NOT supported because
@@ -1983,7 +2002,7 @@ proc `[]=`*[T](s: var seq[T], x: TSlice[int], b: openArray[T]) =
   if L == b.len:
     for i in 0 .. <L: s[i+a] = b[i]
   else:
-    raise newException(EOutOfRange, "differing lengths for slice assignment")
+    spliceImpl(s, x.a, x.b, b)
 
 proc getTypeInfo*[T](x: T): pointer {.magic: "GetTypeInfo".}
   ## get type information for `x`. Ordinary code should not use this, but

tests/accept/run/tunit.nim

@@ -0,0 +1,47 @@
+import
+  unittest, macros
+
+var
+    a = 1
+    b = 22
+    c = 1
+    d = 3
+
+suite "my suite":
+  setup:
+    echo "suite setup"
+    var testVar = "from setup"
+    
+  teardown:
+    echo "suite teardown"
+
+  test "first suite test":
+    testVar = "modified"
+    echo "test var: " & testVar
+    check a > b
+
+  test "second suite test":
+    echo "test var: " & testVar
+
+proc foo: bool =
+  echo "running foo"
+  return true
+
+proc err =
+  raise newException(EArithmetic, "some exception")
+
+test "final test":
+  echo "inside suite-less test"
+
+  check:
+    a == c
+    foo()
+    d > 10
+
+test "arithmetic failure":
+  expect(EArithmetic):
+    err()
+
+  expect(EArithmetic, ESystem):
+    discard foo()
+