From: NeilBrown <neil@brown.name>
Date: Mon, 20 Dec 2021 20:34:06 +0000 (+1100)
Subject: oceani: remove "and then" and "or else"
X-Git-Url: https://ocean-lang.org/code/?p=ocean;a=commitdiff_plain;h=37c2482809a970e5c452f4e3f43d9ee8e18fd141

oceani: remove "and then" and "or else"

I can't think of any reason that "and" and "or" shouldn't be
short-circuit operators, so change them to do what "and then" and "or
else" currently do, and discard the latter.

Signed-off-by: NeilBrown <neil@brown.name>
---

diff --git a/csrc/oceani-tests.mdc b/csrc/oceani-tests.mdc
index 6759c54..0feb0d2 100644
--- a/csrc/oceani-tests.mdc
+++ b/csrc/oceani-tests.mdc
@@ -274,12 +274,12 @@ Now we need to test if/else and some different loops
 		print "error is ", target - guess * guess
 
 		for j:=0; then j = j+3 ; while j < 10:
-			if j != 0 and then 20 / j > 3:
+			if j != 0 and 20 / j > 3:
 				print "20 /", j," =", 20 / j
 			else
 				print "I won't calculate 20 /", j
 		pi ::= 3.1415926535897
-		if 355/113 == pi or else +(pi - 355/113) < 0.001:
+		if 355/113 == pi or +(pi - 355/113) < 0.001:
 			print "Close enough"
 		print "lower" if 355/113 < pi else "higher"
 		print "higher" if 355/113 > pi else "lower"
@@ -781,7 +781,7 @@ A simple linked list example
 
 	func insert(list:@linkage; new:string)
 		p:=list
-		while ?p.next and then p.next.this < new:
+		while ?p.next and p.next.this < new:
 			p = p.next.list
 		t:@node = @new()
 		t.list.next = p.next
diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc
index 910d095..d40a548 100644
--- a/csrc/oceani.mdc
+++ b/csrc/oceani.mdc
@@ -37,9 +37,9 @@ boolean operators.
 
 Some operators that have only recently been added, and so have not
 generated all that much experience yet are "and then" and "or else" as
-short-circuit Boolean operators, and the "if ... else" trinary
-operator which can select between two expressions based on a third
-(which appears syntactically in the middle).
+short-circuit Boolean operators (which have since been remove), and the
+"if ...  else" trinary operator which can select between two expressions
+based on a third (which appears syntactically in the middle).
 
 The "func" clause currently only allows a "main" function to be
 declared.  That will be extended when proper function support is added.
@@ -3932,15 +3932,12 @@ lists.  In that case a separate function is used to print them.
 ### Expressions: Boolean
 
 The next class of expressions to use the `binode` will be Boolean
-expressions.  "`and then`" and "`or else`" are similar to `and` and `or`
-have same corresponding precendence.  The difference is that they don't
+expressions.  `and` and `or` are short-circuit operators that don't
 evaluate the second expression if not necessary.
 
 ###### Binode types
 	And,
-	AndThen,
 	Or,
-	OrElse,
 	Not,
 
 ###### declare terminals
@@ -3956,14 +3953,6 @@ evaluate the second expression if not necessary.
 		b->right = $<3;
 		$0 = b;
 	} }$
-	| Expression or else Expression ${ {
-		struct binode *b = new(binode);
-		b->op = OrElse;
-		b->left = $<1;
-		b->right = $<4;
-		$0 = b;
-	} }$
-
 	| Expression and Expression ${ {
 		struct binode *b = new(binode);
 		b->op = And;
@@ -3971,14 +3960,6 @@ evaluate the second expression if not necessary.
 		b->right = $<3;
 		$0 = b;
 	} }$
-	| Expression and then Expression ${ {
-		struct binode *b = new(binode);
-		b->op = AndThen;
-		b->left = $<1;
-		b->right = $<4;
-		$0 = b;
-	} }$
-
 	| not Expression ${ {
 		struct binode *b = new(binode);
 		b->op = Not;
@@ -3994,13 +3975,6 @@ evaluate the second expression if not necessary.
 		print_exec(b->right, -1, bracket);
 		if (bracket) printf(")");
 		break;
-	case AndThen:
-		if (bracket) printf("(");
-		print_exec(b->left, -1, bracket);
-		printf(" and then ");
-		print_exec(b->right, -1, bracket);
-		if (bracket) printf(")");
-		break;
 	case Or:
 		if (bracket) printf("(");
 		print_exec(b->left, -1, bracket);
@@ -4008,13 +3982,6 @@ evaluate the second expression if not necessary.
 		print_exec(b->right, -1, bracket);
 		if (bracket) printf(")");
 		break;
-	case OrElse:
-		if (bracket) printf("(");
-		print_exec(b->left, -1, bracket);
-		printf(" or else ");
-		print_exec(b->right, -1, bracket);
-		if (bracket) printf(")");
-		break;
 	case Not:
 		if (bracket) printf("(");
 		printf("not ");
@@ -4024,9 +3991,7 @@ evaluate the second expression if not necessary.
 
 ###### propagate binode cases
 	case And:
-	case AndThen:
 	case Or:
-	case OrElse:
 	case Not:
 		/* both must be Tbool, result is Tbool */
 		propagate_types(b->left, c, perr, Tbool, 0);
@@ -4039,21 +4004,11 @@ evaluate the second expression if not necessary.
 
 ###### interp binode cases
 	case And:
-		rv = interp_exec(c, b->left, &rvtype);
-		right = interp_exec(c, b->right, &rtype);
-		rv.bool = rv.bool && right.bool;
-		break;
-	case AndThen:
 		rv = interp_exec(c, b->left, &rvtype);
 		if (rv.bool)
 			rv = interp_exec(c, b->right, NULL);
 		break;
 	case Or:
-		rv = interp_exec(c, b->left, &rvtype);
-		right = interp_exec(c, b->right, &rtype);
-		rv.bool = rv.bool || right.bool;
-		break;
-	case OrElse:
 		rv = interp_exec(c, b->left, &rvtype);
 		if (!rv.bool)
 			rv = interp_exec(c, b->right, NULL);
@@ -5998,7 +5953,7 @@ things which will likely grow as the languages grows.
 		a : number
 		a = A;
 		b:number = B
-		if a > 0 and then b > 0:
+		if a > 0 and b > 0:
 			while a != b:
 				if a < b:
 					b = b - a