From 69756809ef2d0324ec94b277f9750f92db4ae416 Mon Sep 17 00:00:00 2001
From: NeilBrown <neil@brown.name>
Date: Wed, 10 Nov 2021 21:27:50 +1100
Subject: [PATCH] oceani: remove the need for 'then' in function declarations.

Previously an IN had to follow a terminal because it would never for a
reduce.
This made is a problem for
    func FuncName
          arguments
    do
          code

as the IN follows FuncName - a non-terminal.

Fix this by allowing an IN to force a reduce if nothing at all can be
shifted.
After "func IDENTIFIER", nothing can be shifted.  The IDENTIFIER must be
reduced to FuncName.  At that point, the IN is expected, so it won't be
ignored.

This allows the 'then' to be dropped.

Signed-off-by: NeilBrown <neil@brown.name>
---
 csrc/oceani-tests.mdc |  4 ++--
 csrc/oceani.mdc       |  3 +--
 csrc/parsergen.mdc    | 15 ++++++++-------
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/csrc/oceani-tests.mdc b/csrc/oceani-tests.mdc
index d9be788..2314ce3 100644
--- a/csrc/oceani-tests.mdc
+++ b/csrc/oceani-tests.mdc
@@ -620,7 +620,7 @@ Test functions.  They don't return anything, so we need to get them to print
 
 ###### test: functions
 
-	func test1 then
+	func test1
 		t: Boolean
 	do
 		if t:
@@ -971,7 +971,7 @@ Test for type errors with functions
 	do
 		pass
 
-	func test1 then
+	func test1
 		b:Boolean
 	do
 		pass
diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc
index f257736..590add2 100644
--- a/csrc/oceani.mdc
+++ b/csrc/oceani.mdc
@@ -4718,8 +4718,7 @@ analysis is a bit more interesting at this level.
 			} else
 				var_block_close(c, CloseSequential, NULL);
 		} }$
-		| func FuncName then IN OpenScope OptNL Args OUT OptNL do Block Newlines ${ {
-			// FIXME that 'then' should not be there.
+		| func FuncName IN OpenScope OptNL Args OUT OptNL do Block Newlines ${ {
 			struct text funcname = { " func", 5};
 			$0 = $<FN;
 			if ($0) {
diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index 80027aa..6cb5a73 100644
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -2785,11 +2785,12 @@ might also be ignored.  Ignoring tokens is combined with shifting.
 	}
 
 Indents are ignored unless they can be shifted onto the stack
-immediately.  The end of an indented section - the OUT token - is
-ignored precisely when the indent was ignored.  To keep track of this we
-need a small stack of flags, which is easily stored as bits in an
-`unsigned long`.  This will never overflow and the scanner only allows
-20 levels of indentation.
+immediately or nothing can be shifted (in which case we reduce, and try
+again).  The end of an indented section - the OUT token - is ignored
+precisely when the indent was ignored.  To keep track of this we need a
+small stack of flags, which is easily stored as bits in an `unsigned
+long`.  This will never overflow and the scanner only allows 20 levels
+of indentation.
 
 ###### parser state
 	unsigned long ignored_indents;
@@ -2829,8 +2830,8 @@ we try to reduce a production.
 		continue;
 	}
 
-	if (tk->num == TK_in) {
-		/* No indent expected here, so ignore IN */
+	if (tk->num == TK_in && states[p.stack[p.tos-1].state].go_to_cnt > 0) {
+		/* No indent expected here and reduce is not mandatory, so ignore IN */
 		free(tk);
 		tk = NULL;
 		p.ignored_indents <<= 1;
-- 
2.43.0