Implement single-line C++-style comments.

Fixes: #118

lang/cem/cemcom.ansi/LLlex.c

@@ -53,6 +53,7 @@ static struct token LexStack[MAX_LL_DEPTH];
 static LexSP = 0;
 
 void skipcomment();
+void skiplinecomment();
 
 /*	In PushLex() the actions are taken in order to initialise or
     re-initialise the lexical scanner.
@@ -168,12 +169,13 @@ go_on: /* rescan, the following character has been read	*/
 						goto firstline;
 					}
 				}
-				else if (ch == '/')
+				else if ((ch == '/') && !InputLevel)
 				{
-					if ((GetChar() == '*') && !InputLevel)
+					int nch = GetChar();
-					{
+					if (nch == '*')
 						skipcomment();
-					}
+					else if (nch == '/')
+						skiplinecomment();
 					else
 					{
 						UnGetChar();
@@ -284,10 +286,18 @@ go_on: /* rescan, the following character has been read	*/
 					break;
 				case '/':
 #ifndef NOPP
-					if (nch == '*' && !InputLevel)
+					if (!InputLevel)
 					{
-						skipcomment();
+						if (nch == '*')
-						goto again;
+						{
+							skipcomment();
+							goto again;
+						}
+						else if (nch == '/')
+						{
+							skiplinecomment();
+							goto again;
+						}
 					}
 #endif
 					if (nch == '=')
@@ -539,6 +549,22 @@ void skipcomment()
 #endif /* LINT */
 	NoUnstack--;
 }
+
+void skiplinecomment(void)
+{
+	/*	The last character read has been the '/' of '//'. We read
+	    and discard all characters up to but not including the next
+		NL. */
+	
+	for (;;) {
+		int c = GetChar();
+		if ((class(c) == STNL) || (c == EOI))
+		{
+			UnGetChar();
+			break;
+		}
+	}
+}
 #endif /* NOPP */
 
 arith char_constant(nm) char* nm;

lang/cem/cemcom.ansi/domacro.c

@@ -190,13 +190,18 @@ void skip_block(to_endif) int to_endif;
 			if (ch == '/')
 			{
 				ch = GetChar();
-				if (ch != '*')
+				if (ch == '/')
-					UnGetChar();
+				{
-				else
+					skiplinecomment();
+					continue;
+				}
+				else if (ch == '*')
 				{
 					skipcomment();
 					continue;
 				}
+				else
+					UnGetChar();
 			}
 			else
 				UnGetChar();
@@ -748,6 +753,13 @@ int* length;
 				c = GetChar();
 				continue;
 			}
+			else if (c == '/')
+			{
+				skiplinecomment();
+				blank++;
+				c = GetChar();
+				continue;
+			}
 			if (blank)
 			{
 				blank = 0;

lang/cem/cemcom.ansi/skip.c

@@ -48,6 +48,11 @@ int skipspaces(ch, skipnl) register int ch;
 				skipcomment();
 				ch = GetChar();
 			}
+			else if (ch == '/' && !InputLevel)
+			{
+				skiplinecomment();
+				ch = GetChar();
+			}
 			else
 			{
 				UnGetChar();
@@ -96,13 +101,22 @@ SkipToNewLine()
 		}
 		else if (ch == '/')
 		{
-			if (GetChar() == '*' && !InputLevel)
+			if (!InputLevel)
 			{
-				skipcomment();
+				int nch = GetChar();
-				continue;
+				if (nch == '*')
+				{
+					skipcomment();
+					continue;
+				}
+				else if (nch == '/')
+				{
+					skiplinecomment();
+					continue;
+				}
+				else
+					UnGetChar();
 			}
-			else
-				UnGetChar();
 		}
 		else if (ch == TOKSEP && InputLevel)
 		{

lang/cem/cpp.ansi/LLlex.c

@@ -36,6 +36,7 @@ extern arith char_constant();
 #define FLG_DOTSEEN 0x02 /* certainly a floating point number */
 
 void skipcomment();
+void skiplinecomment(void);
 
 int LLlex()
 {
@@ -165,10 +166,18 @@ again: /* rescan the input after an error or replacement	*/
 					UnGetChar();
 					return ptok->tk_symb = ch;
 				case '/':
-					if (nch == '*' && !InputLevel)
+					if (!InputLevel)
 					{
-						skipcomment();
+						if (nch == '*')
-						goto again;
+						{
+							skipcomment();
+							goto again;
+						}
+						else if (nch == '/')
+						{
+							skiplinecomment();
+							goto again;
+						}
 					}
 					else if (nch == '=')
 						return ptok->tk_symb = DIVAB;
@@ -412,6 +421,22 @@ void skipcomment()
 	NoUnstack--;
 }
 
+void skiplinecomment(void)
+{
+	/*	The last character read has been the '/' of '//'. We read
+	    and discard all characters up to but not including the next
+		NL. */
+	
+	for (;;) {
+		int c = GetChar();
+		if ((class(c) == STNL) || (c == EOI))
+		{
+			UnGetChar();
+			break;
+		}
+	}
+}
+
 arith char_constant(nm) char* nm;
 {
 	register arith val = 0;

lang/cem/cpp.ansi/domacro.c

@@ -187,13 +187,18 @@ void skip_block(to_endif) int to_endif;
 			}
 			if (ch == '/')
 			{
-				if (ch != '*')
+				if (ch == '*')
-					UnGetChar();
-				else
 				{
 					skipcomment();
 					continue;
 				}
+				else if (ch == '/')
+				{
+					skiplinecomment();
+					continue;
+				}
+				else
+					UnGetChar();
 			}
 			else
 				UnGetChar();
@@ -769,6 +774,13 @@ int* length;
 				c = GetChar();
 				continue;
 			}
+			else if (c == '/')
+			{
+				skiplinecomment();
+				blank++;
+				c = GetChar();
+				continue;
+			}
 			if (blank)
 			{
 				blank = 0;

lang/cem/cpp.ansi/preprocess.c

@@ -81,15 +81,21 @@ do_pragma()
 		}
 		else if (c == '/')
 		{
-			if ((c = GetChar()) != '*' || InputLevel)
+			if (!InputLevel)
 			{
+				c = GetChar();
+				if (c == '*')
+				{
+					skipcomment();
+					continue;
+				}
+				else if (c == '/')
+				{
+					skiplinecomment();
+					continue;
+				}
 				*c_ptr++ = '/';
 			}
-			else
-			{
-				skipcomment();
-				continue;
-			}
 		}
 		*c_ptr++ = c;
 		c = GetChar();
@@ -238,6 +244,12 @@ void preprocess(fn) char* fn;
 							c = GetChar();
 							continue;
 						}
+						else if (c == '/')
+						{
+							skiplinecomment();
+							c = GetChar();
+							continue;
+						}
 						UnGetChar();
 						c = '/';
 					}
@@ -290,6 +302,12 @@ void preprocess(fn) char* fn;
 					c = GetChar();
 					continue;
 				}
+				else if (c == '/')
+				{
+					skiplinecomment();
+					c = GetChar();
+					continue;
+				}
 				echo('/');
 				continue;
 			}

lang/cem/cpp.ansi/skip.c

@@ -46,6 +46,11 @@ int skipspaces(ch, skipnl) register int ch;
 				skipcomment();
 				ch = GetChar();
 			}
+			else if (ch == '/' && !InputLevel)
+			{
+				skiplinecomment();
+				ch = GetChar();
+			}
 			else
 			{
 				UnGetChar();
@@ -90,13 +95,22 @@ SkipToNewLine()
 		}
 		else if (ch == '/')
 		{
-			if (GetChar() == '*' && !InputLevel)
+			if (!InputLevel)
 			{
-				skipcomment();
+				int nch = GetChar();
-				continue;
+				if (nch == '*')
+				{
+					skipcomment();
+					continue;
+				}
+				else if (nch == '/')
+				{
+					skiplinecomment();
+					continue;
+				}
+				else
+					UnGetChar();
 			}
-			else
-				UnGetChar();
 		}
 		else if (ch == TOKSEP && InputLevel)
 		{