Ticket #211: implicit-line-cont.patch

Source/CobraTokenizer.cobra

@@ -425 +425 @@
                 firstTok = lastTok = newTok
         return firstTok
 
-    var _didLineContinuation as bool  # only meaningful after an EOL
+    var _didLineContinuation as bool  
+        """ 
+        True if had an explicit (or implicit) line continuation char just before an EOL
+        Only meaningful after an EOL.
+        """
+    # List of binary ops that can act as implicit line continuation, ordered by approx freq of use
+    var implicitContinuationOps = [ 
+        'ASSIGN', 'AND', 'OR', 'STAR', 'SLASH', 'PLUS',
+        'MINUS','EQ', 'NE', 'LT', 'LE', 'GT', 'GE', 'IN', 'NOTIN',
+        'PLUS_EQUALS', 'MINUS_EQUALS', 'STAR_EQUALS', 'SLASH_EQUALS', 'PERCENT_EQUALS',
+        'SLASHSLASH', 'PERCENT', 'AMPERSAND', 'VERTICAL_BAR', 'CARET', 'DOUBLE_LT',
+        'DOUBLE_GT', 'AMPERSAND_EQUALS', 'VERTICAL_BAR_EQUALS', 'CARET_EQUALS', 
+        'DOUBLE_LT_EQUALS', 'DOUBLE_GT_EQUALS', 'STARSTAR', 'STARSTAR_EQUALS' 
+    ] 
 
+    var _seenSuppressor = false
+        """
+        Record if have seen keywords on current line that may indicate a trailing implicit
+            line continuation token is not part of an expression
+        """
+    
     get justDidLineContinuation as bool
         return .lastToken and .lastToken.which == 'EOL' and _didLineContinuation
 
     def onEOL(tok as IToken) as IToken?
         _didLineContinuation = .lastToken and .lastToken.text == '_' and .lastToken.which == 'ID'
+        if not _didLineContinuation and .lastToken 
+            _didLineContinuation = .lastToken.which in .implicitContinuationOps
+            # These below need special handling to avoid false positives for trailing 
+            # type declarations of streams (*) and generics (>)
+            if (.lastToken.which == 'STAR' or .lastToken.which == 'GT')  and _seenSuppressor
+                _didLineContinuation = false
+            #if _didLineContinuation
+            #   print .lastToken, .lastToken.fileName, .lastToken.lineNum, _didLineContinuation
+        _seenSuppressor = false
         return tok
 
     def onSINGLE_LINE_COMMENT(tok as IToken) as IToken?
@@ -463 +491 @@
         require tok.text.trim.endsWith('<of')
         s = tok.text.trim
         tok.value = s[:-3]
+        if not _seenSuppressor, _seenSuppressor = true
         return tok
-
+        
+    var _keywordsSuppressingILCont = ['DEF', 'CLASS', 'STRUCT', 'AS', 'IMPLEMENTS', 'INHERITS'] 
+        """ Keywords suppressing implicit line continuation from a trailing operator token"""
+    
     def onID(tok as IToken) as IToken?
         tok = .keywordOrWhich(tok, 'ID')
         if tok.which<>'ID'
             tok.isKeyword = true
+            if not _seenSuppressor
+                _seenSuppressor = (tok.which in _keywordsSuppressingILCont)
         return tok
 
     def onFLOAT_LIT_1(tok as IToken) as IToken?

Source/CobraParser.cobra

@@ -2904 +2904 @@
             else
                 if .opStack.count and .opStack.peek=='DOT' and .peek.isKeyword
                     return .identifierExpr
-                else
+                else if .peek.which =='EOL' and .last.which in _tokenizer.implicitContinuationOps
+                    # trailing op on EOL - implicit line continuation
+                    .grab
+                    return .expression2
+                else        
                     try
                         return .typeExpr
                     catch pe as ParserException

Tests/110-basics-two/150-line-continuation/120-implicit-line-cont-ops.cobra

@@ +1 @@
+# Test for implicit forms of line continuation: round brackets and trailing binary ops
+# ticket:211 (partially also addresses ticket 210)
+class Program
+
+    def main
+        assert 1 + 2 == 3       # ok
+            
+        assert (1 +     # braces ok
+            2) == 3
+        assert 1 *      # implicit trailing '*', 0 indent
+        2  == 2
+        
+        assert 1 +      # implicit trailing '+', 1 indent
+            2 == 3
+        assert (1 +     # Ticket 210: Cannot mix tabs and spaces in indentation.
+               2)
+        assert 1 +      # Both tickets.
+              2 == 3
+
+        assert (1 +     # braces, double indent
+                12) == 13
+        assert 1 +      # trailing '+', double indent after
+                2 == 3
+        assert 3 -      # trailing '-', double indent after
+                2 == 1
+                
+        assert 3 *      # ((3*1) + 4) -(8/2)
+            1 +
+            4 -
+            8 /
+            2 == 3
+            
+        a = 1
+        b = 2
+        assert (a == 1 and  
+            b == 2)
+        assert a == 1 and   #implicit on 'and'
+            b == 2
+        assert a == 1 or    # implicit on or
+            b == 2
+
+        assert a == 1 and   # implicit on and and tabs+spaces
+               b == 2
+
+            

Developer/IntermediateReleaseNotes.text

@@ -505 +505 @@
 * Fixed: In combination with the directive `@number float32`, negative numeric literals such as "-1.0" can cause a false compilation error about types. reported-by:Gekko
 
 * Fixed: A nil/null field in the a library caused the compiler to throw an exception.
+
+* Fixed: Add implicit line continuation for lines ending in an expression with a trailing operator. ticket:211