From: Michael D. Lowis <mike.lowis@gentex.com>
Date: Wed, 21 Apr 2021 20:25:41 +0000 (-0400)
Subject: reformatted OSP.mod for readability. Started building parser rules for statements... 
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=018c0d2a33b414b500cd338e12e917baa87ba03e;p=proto%2Fobnc.git

reformatted OSP.mod for readability. Started building parser rules for statements. Focusing on if statements, assignments, and function calls first
---

diff --git a/cerise/oberon0/OSP.Mod b/cerise/oberon0/OSP.Mod
index 58be0a2..4433549 100644
--- a/cerise/oberon0/OSP.Mod
+++ b/cerise/oberon0/OSP.Mod
@@ -284,62 +284,123 @@ MODULE OSP; (* NW 23.9.93 / 9,5.2017   OSPX*)
   PROCEDURE StatSequence;
     VAR par, obj: OSG.Object; x, y: OSG.Item; n, L: LONGINT;
   BEGIN (* StatSequence *)
-    REPEAT (*sync*) obj := NIL;
+    REPEAT (*sync*)
+      obj := NIL;
       IF ~((sym = OSS.ident) OR (sym >= OSS.if) & (sym <= OSS.repeat) OR (sym >= OSS.semicolon)) THEN
         OSS.Mark("statement expected");
         REPEAT OSS.Get(sym) UNTIL (sym = OSS.ident) OR (sym >= OSS.if)
       END ;
+
       IF sym = OSS.ident THEN
-        find(obj); OSS.Get(sym);
-        IF obj.class = OSG.SProc THEN StandProc(obj.val)
-        ELSE OSG.MakeItem(x, obj, level); selector(x);
+        find(obj);
+        OSS.Get(sym);
+        IF obj.class = OSG.SProc THEN
+          StandProc(obj.val)
+        ELSE
+          OSG.MakeItem(x, obj, level);
+          selector(x);
           IF sym = OSS.becomes THEN (*assignment*)
-            OSS.Get(sym); expression(y);
-            IF (x.type.form IN {OSG.Boolean, OSG.Integer}) & (x.type.form = y.type.form) THEN OSG.Store(x, y)
-            ELSE OSS.Mark("incompatible assignment")
+            OSS.Get(sym);
+            expression(y);
+            IF (x.type.form IN {OSG.Boolean, OSG.Integer}) & (x.type.form = y.type.form) THEN
+              OSG.Store(x, y)
+            ELSE
+              OSS.Mark("incompatible assignment")
             END
-          ELSIF sym = OSS.eql THEN OSS.Mark("should be :="); OSS.Get(sym); expression(y)
+          ELSIF sym = OSS.eql THEN
+            OSS.Mark("should be :=");
+            OSS.Get(sym);
+            expression(y)
           ELSIF sym = OSS.lparen THEN (*procedure call*)
             OSS.Get(sym);
-            IF (obj.class = OSG.Proc) & (obj.type = NIL) THEN ParamList(obj); OSG.Call(obj);
-            ELSE OSS.Mark("not a procedure")
+            IF (obj.class = OSG.Proc) & (obj.type = NIL) THEN
+              ParamList(obj);
+              OSG.Call(obj);
+            ELSE
+              OSS.Mark("not a procedure")
             END
           ELSIF obj.class = OSG.Proc THEN (*procedure call without parameters*)
-            IF obj.nofpar > 0 THEN OSS.Mark("missing parameters") END ;
-            IF obj.type = NIL THEN OSG.Call(obj) ELSE OSS.Mark("not a procedure") END
-          ELSIF (obj.class = OSG.SProc) & (obj.val = 3) THEN OSG.WriteLn
-          ELSIF obj.class = OSG.Typ THEN OSS.Mark("illegal assignment")
-          ELSE OSS.Mark("not a procedure")
+            IF obj.nofpar > 0 THEN
+              OSS.Mark("missing parameters")
+            END ;
+            IF obj.type = NIL THEN
+              OSG.Call(obj) ELSE
+              OSS.Mark("not a procedure")
+            END
+          ELSIF (obj.class = OSG.SProc) & (obj.val = 3) THEN
+            OSG.WriteLn
+          ELSIF obj.class = OSG.Typ THEN
+            OSS.Mark("illegal assignment")
+          ELSE
+            OSS.Mark("not a procedure")
           END
         END
       ELSIF sym = OSS.if THEN
-        OSS.Get(sym); expression(x); CheckBool(x); OSG.CFJump(x); Check(OSS.then, "no THEN");
-        StatSequence; L := 0;
+        OSS.Get(sym);
+        expression(x);
+        CheckBool(x);
+        OSG.CFJump(x);
+        Check(OSS.then, "no THEN");
+        StatSequence;
+        L := 0;
         WHILE sym = OSS.elsif DO
-          OSS.Get(sym); OSG.FJump(L); OSG.FixLink(x.a); expression(x); CheckBool(x); OSG.CFJump(x);
-          IF sym = OSS.then THEN OSS.Get(sym) ELSE OSS.Mark("THEN?") END ;
+          OSS.Get(sym);
+          OSG.FJump(L);
+          OSG.FixLink(x.a);
+          expression(x);
+          CheckBool(x);
+          OSG.CFJump(x);
+          IF sym = OSS.then THEN
+            OSS.Get(sym)
+          ELSE
+            OSS.Mark("THEN?")
+          END ;
           StatSequence
         END ;
         IF sym = OSS.else THEN
-          OSS.Get(sym); OSG.FJump(L); OSG.FixLink(x.a); StatSequence
-        ELSE OSG.FixLink(x.a)
+          OSS.Get(sym);
+          OSG.FJump(L);
+          OSG.FixLink(x.a);
+          StatSequence
+        ELSE
+          OSG.FixLink(x.a)
         END ;
         OSG.FixLink(L);
-        IF sym = OSS.end THEN OSS.Get(sym) ELSE OSS.Mark("END?") END
+        IF sym = OSS.end THEN
+          OSS.Get(sym)
+        ELSE
+          OSS.Mark("END?")
+        END
       ELSIF sym = OSS.while THEN
-        OSS.Get(sym); L := OSG.pc; expression(x); CheckBool(x); OSG.CFJump(x);
-        Check(OSS.do, "no DO"); StatSequence; OSG.BJump(L); OSG.FixLink(x.a);
+        OSS.Get(sym);
+        L := OSG.pc;
+        expression(x);
+        CheckBool(x);
+        OSG.CFJump(x);
+        Check(OSS.do, "no DO");
+        StatSequence;
+        OSG.BJump(L);
+        OSG.FixLink(x.a);
         Check(OSS.end, "no END")
       ELSIF sym = OSS.repeat THEN
-        OSS.Get(sym); L := OSG.pc; StatSequence;
+        OSS.Get(sym);
+        L := OSG.pc;
+        StatSequence;
         IF sym = OSS.until THEN
-          OSS.Get(sym); expression(x); CheckBool(x); OSG.CBJump(x, L)
-        ELSE OSS.Mark("missing UNTIL"); OSS.Get(sym)
+          OSS.Get(sym);
+          expression(x);
+          CheckBool(x);
+          OSG.CBJump(x, L)
+        ELSE
+          OSS.Mark("missing UNTIL");
+          OSS.Get(sym)
         END
       END ;
       OSG.CheckRegs;
-      IF sym = OSS.semicolon THEN OSS.Get(sym)
-      ELSIF sym < OSS.semicolon THEN OSS.Mark("missing semicolon?")
+      IF sym = OSS.semicolon THEN
+        OSS.Get(sym)
+      ELSIF sym < OSS.semicolon THEN
+        OSS.Mark("missing semicolon?")
       END
     UNTIL sym > OSS.semicolon
   END StatSequence;
@@ -518,6 +579,7 @@ MODULE OSP; (* NW 23.9.93 / 9,5.2017   OSPX*)
       Check(OSS.semicolon, "; expected");
       Declarations(dc);
       WHILE sym = OSS.procedure DO ProcedureDecl; Check(OSS.semicolon, "; expected") END ;
+
       OSG.Header(dc);
       IF sym = OSS.begin THEN OSS.Get(sym); StatSequence END ;
       Check(OSS.end, "no END");
diff --git a/cerise/parser.c b/cerise/parser.c
index e166ccb..d3ca8f9 100644
--- a/cerise/parser.c
+++ b/cerise/parser.c
@@ -471,7 +471,26 @@ RULE(const_decl)
 
 RULE(statement_seq)
 {
-    (void)p, (void)item;
+    (void)item;
+    if (matches(p, IDENT))
+    {
+        if (accept(p, '='))
+        {
+
+        }
+        else
+        {
+            error(p, "expected assignment");
+        }
+    }
+    else if (matches(p, IF))
+    {
+    }
+    else
+    {
+        error(p, "expected a statement");
+    }
+    expect(p, ';');
 }
 
 RULE(declaration_seq)
@@ -481,16 +500,20 @@ RULE(declaration_seq)
         const_decl(p, item);
         expect(p, ';');
     }
+
     if (accept(p, TYPE))
     {
         type_decl(p, item);
         expect(p, ';');
     }
+
     if (accept(p, VAR))
     {
         var_decl(p, item);
         expect(p, ';');
     }
+
+    /* WHILE sym = OSS.procedure DO ProcedureDecl; Check(OSS.semicolon, "; expected") END ; */
 }
 
 RULE(import_list)