Add compiling of boolean expressions to stack IR

Author: dibyendumajumdar

stackvm/src/main/java/com/compilerprogramming/ezlang/compiler/CompiledFunction.java

@@ -343,15 +343,47 @@ private boolean compileSymbolExpr(AST.NameExpr symbolExpr) {
         return false;
     }
 
+    private boolean codeBoolean(AST.BinaryExpr binaryExpr) {
+        boolean isAnd = binaryExpr.op.str.equals("&&");
+        BasicBlock l1 = createBlock();
+        BasicBlock l2 = createBlock();
+        BasicBlock l3 = createBlock();
+        boolean indexed = compileExpr(binaryExpr.expr1);
+        if (indexed)
+            codeIndexedLoad();
+        if (isAnd) {
+            code(new Instruction.ConditionalBranch(currentBlock, l1, l2));
+        } else {
+            code(new Instruction.ConditionalBranch(currentBlock, l2, l1));
+        }
+        startBlock(l1);
+        indexed = compileExpr(binaryExpr.expr2);
+        if (indexed)
+            codeIndexedLoad();
+        jumpTo(l3);
+        startBlock(l2);
+        // Below we must write to the same temp
+        code(new Instruction.PushConst(isAnd ? 0 : 1));
+        jumpTo(l3);
+        startBlock(l3);
+        // leaves result on stack
+        return false;
+    }
+
     private boolean compileBinaryExpr(AST.BinaryExpr binaryExpr) {
+        String binOp = binaryExpr.op.str;
+        if (binOp.equals("&&") ||
+                binOp.equals("||")) {
+            return codeBoolean(binaryExpr);
+        }
         int opCode = 0;
         boolean indexed = compileExpr(binaryExpr.expr1);
         if (indexed)
             codeIndexedLoad();
         indexed = compileExpr(binaryExpr.expr2);
         if (indexed)
             codeIndexedLoad();
-        switch (binaryExpr.op.str) {
+        switch (binOp) {
             case "+" -> opCode = Instruction.ADD_I;
             case "-" -> opCode = Instruction.SUB_I;
             case "*" -> opCode = Instruction.MUL_I;

stackvm/src/test/java/com/compilerprogramming/ezlang/compiler/TestCompiler.java

@@ -634,4 +634,34 @@ public void testFunction28() {
 L1:
 """, result);
     }
+
+    @Test
+    public void testFunction104() {
+        String src = """
+                func foo()->Int
+                {
+                    return 1 == 1 && 2 == 2
+                }
+                """;
+        String result = compileSrc(src);
+        Assert.assertEquals("""
+L0:
+	pushi 1
+	pushi 1
+	eq
+	cbr L2 L3
+L2:
+	pushi 2
+	pushi 2
+	eq
+	jump L4
+L4:
+	jump L1
+L1:
+L3:
+	pushi 0
+	jump L4
+""", result);
+    }
+
 }