nimpretty improvements

compiler/layouter.nim

@@ -7,10 +7,7 @@
 #    distribution, for details about the copyright.
 #
 
-## Layouter for nimpretty. Still primitive but useful.
-## TODO
-## - Make indentations consistent.
-## - Align 'if' and 'case' expressions properly.
+## Layouter for nimpretty.
 
 import idents, lexer, lineinfos, llstream, options, msgs, strutils
 from os import changeFileExt
@@ -30,14 +27,20 @@ type
     lastTok: TTokType
     inquote: bool
     col, lastLineNumber, lineSpan, indentLevel, indWidth: int
-    lastIndent: int
+    nested: int
     doIndentMore*: int
     content: string
+    indentStack: seq[int]
     fixedUntil: int # marks where we must not go in the content
     altSplitPos: array[SplitKind, int] # alternative split positions
 
-proc openEmitter*(em: var Emitter, config: ConfigRef, fileIdx: FileIndex) =
-  let outfile = changeFileExt(config.toFullPath(fileIdx), ".pretty.nim")
+proc openEmitter*(em: var Emitter, cache: IdentCache;
+                  config: ConfigRef, fileIdx: FileIndex) =
+  let fullPath = config.toFullPath(fileIdx)
+  em.indWidth = getIndentWidth(fileIdx, llStreamOpen(fullPath, fmRead),
+                               cache, config)
+  if em.indWidth == 0: em.indWidth = 2
+  let outfile = changeFileExt(fullPath, ".pretty.nim")
   em.f = llStreamOpen(outfile, fmWrite)
   em.config = config
   em.fid = fileIdx
@@ -45,6 +48,8 @@ proc openEmitter*(em: var Emitter, config: ConfigRef, fileIdx: FileIndex) =
   em.inquote = false
   em.col = 0
   em.content = newStringOfCap(16_000)
+  em.indentStack = newSeqOfCap[int](30)
+  em.indentStack.add 0
   if em.f == nil:
     rawMessage(config, errGenerated, "cannot open file: " & outfile)
 
@@ -74,14 +79,15 @@ const
   splitters = {tkComma, tkSemicolon, tkParLe, tkParDotLe,
                tkBracketLe, tkBracketLeColon, tkCurlyDotLe,
                tkCurlyLe}
-  sectionKeywords = {tkType, tkVar, tkConst, tkLet, tkUsing}
+  oprSet = {tkOpr, tkDiv, tkMod, tkShl, tkShr, tkIn, tkNotin, tkIs,
+            tkIsnot, tkNot, tkOf, tkAs, tkDotDot, tkAnd, tkOr, tkXor}
 
 template rememberSplit(kind) =
   if goodCol(em.col):
     em.altSplitPos[kind] = em.content.len
 
 template moreIndent(em): int =
-  max(if em.doIndentMore > 0: em.indWidth*2 else: em.indWidth, 2)
+  (if em.doIndentMore > 0: em.indWidth*2 else: em.indWidth)
 
 proc softLinebreak(em: var Emitter, lit: string) =
   # XXX Use an algorithm that is outlined here:
@@ -96,7 +102,8 @@ proc softLinebreak(em: var Emitter, lit: string) =
       # search backwards for a good split position:
       for a in em.altSplitPos:
         if a > em.fixedUntil:
-          let ws = "\L" & repeat(' ',em.indentLevel+moreIndent(em))
+          let ws = "\L" & repeat(' ',em.indentLevel+moreIndent(em) -
+              ord(em.content[a] == ' '))
           em.col = em.content.len - a
           em.content.insert(ws, a)
           break
@@ -119,10 +126,6 @@ proc emitTok*(em: var Emitter; L: TLexer; tok: TToken) =
     wr lit
 
   var preventComment = false
-  if em.indWidth == 0 and tok.indent > 0:
-    # first indentation determines how many number of spaces to use:
-    em.indWidth = tok.indent
-
   if tok.tokType == tkComment and tok.line == em.lastLineNumber and tok.indent >= 0:
     # we have an inline comment so handle it before the indentation token:
     emitComment(em, tok)
@@ -130,14 +133,17 @@ proc emitTok*(em: var Emitter; L: TLexer; tok: TToken) =
     em.fixedUntil = em.content.high
 
   elif tok.indent >= 0:
-    em.indentLevel = tok.indent
-    # remove trailing whitespace:
-    while em.content.len > 0 and em.content[em.content.high] == ' ':
-      setLen(em.content, em.content.len-1)
-    wr("\L")
-    for i in 2..tok.line - em.lastLineNumber: wr("\L")
-    em.col = 0
-    #[ we only correct the indentation if it is slightly off,
+    if em.lastTok in (splitters + oprSet):
+      em.indentLevel = tok.indent
+    else:
+      if tok.indent > em.indentStack[^1]:
+        em.indentStack.add tok.indent
+      else:
+        # dedent?
+        while em.indentStack.len > 1 and em.indentStack[^1] > tok.indent:
+          discard em.indentStack.pop()
+      em.indentLevel = em.indentStack.high * em.indWidth
+    #[ we only correct the indentation if it is not in an expression context,
        so that code like
 
         const splitters = {tkComma, tkSemicolon, tkParLe, tkParDotLe,
@@ -146,20 +152,15 @@ proc emitTok*(em: var Emitter; L: TLexer; tok: TToken) =
 
        is not touched.
     ]#
-    when false:
-      if tok.indent > em.lastIndent and em.indWidth > 1 and (tok.indent mod em.indWidth) == 1:
-        em.indentLevel = 0
-        while em.indentLevel < tok.indent-1:
-          inc em.indentLevel, em.indWidth
-    when false:
-      if em.indWidth != 0 and
-          abs(tok.indent - em.nested*em.indWidth) <= em.indWidth and
-          em.lastTok notin sectionKeywords:
-        em.indentLevel =  em.nested*em.indWidth
+    # remove trailing whitespace:
+    while em.content.len > 0 and em.content[em.content.high] == ' ':
+      setLen(em.content, em.content.len-1)
+    wr("\L")
+    for i in 2..tok.line - em.lastLineNumber: wr("\L")
+    em.col = 0
     for i in 1..em.indentLevel:
       wr(" ")
     em.fixedUntil = em.content.high
-    em.lastIndent = tok.indent
 
   case tok.tokType
   of tokKeywordLow..tokKeywordHigh:
@@ -168,15 +169,19 @@ proc emitTok*(em: var Emitter; L: TLexer; tok: TToken) =
     elif not em.inquote and not endsInWhite(em):
       wr(" ")
 
-    wr(TokTypeToStr[tok.tokType])
+    if not em.inquote:
+      wr(TokTypeToStr[tok.tokType])
 
-    case tok.tokType
-    of tkAnd: rememberSplit(splitAnd)
-    of tkOr: rememberSplit(splitOr)
-    of tkIn, tkNotin:
-      rememberSplit(splitIn)
-      wr(" ")
-    else: discard
+      case tok.tokType
+      of tkAnd: rememberSplit(splitAnd)
+      of tkOr: rememberSplit(splitOr)
+      of tkIn, tkNotin:
+        rememberSplit(splitIn)
+        wr(" ")
+      else: discard
+    else:
+      # keywords in backticks are not normalized:
+      wr(tok.ident.s)
 
   of tkColon:
     wr(TokTypeToStr[tok.tokType])

compiler/lexer.nim

@@ -867,7 +867,7 @@ proc getOperator(L: var TLexer, tok: var TToken) =
   if buf[pos] in {CR, LF, nimlexbase.EndOfFile}:
     tok.strongSpaceB = -1
 
-proc newlineFollows*(L: var TLexer): bool =
+proc newlineFollows*(L: TLexer): bool =
   var pos = L.bufpos
   var buf = L.buf
   while true:
@@ -1220,3 +1220,15 @@ proc rawGetTok*(L: var TLexer, tok: var TToken) =
         lexMessage(L, errGenerated, "invalid token: " & c & " (\\" & $(ord(c)) & ')')
         inc(L.bufpos)
   atTokenEnd()
+
+proc getIndentWidth*(fileIdx: FileIndex, inputstream: PLLStream;
+                     cache: IdentCache; config: ConfigRef): int =
+  var lex: TLexer
+  var tok: TToken
+  initToken(tok)
+  openLexer(lex, fileIdx, inputstream, cache, config)
+  while true:
+    rawGetTok(lex, tok)
+    result = tok.indent
+    if result > 0 or tok.tokType == tkEof: break
+  closeLexer(lex)

compiler/parser.nim

@@ -102,7 +102,7 @@ proc openParser*(p: var TParser, fileIdx: FileIndex, inputStream: PLLStream,
   initToken(p.tok)
   openLexer(p.lex, fileIdx, inputStream, cache, config)
   when defined(nimpretty2):
-    openEmitter(p.em, config, fileIdx)
+    openEmitter(p.em, cache, config, fileIdx)
   getTok(p)                   # read the first token
   p.firstTok = true
   p.strongSpaces = strongSpaces