New operators 'but' and assignment ('=')

operator-assign.go

@@ -0,0 +1,43 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operator-assign.go
+package expr
+
+import "fmt"
+
+//-------- assign term
+
+func newAssignTerm(tk *Token) (inst *term) {
+	return &term{
+		tk:       *tk,
+		class:    classOperator,
+		kind:     kindUnknown,
+		children: make([]*term, 0, 2),
+		position: posInfix,
+		priority: priAssign,
+		evalFunc: evalAssign,
+	}
+}
+
+func evalAssign(ctx exprContext, self *term) (v any, err error) {
+	if err = self.checkOperands(); err != nil {
+		return
+	}
+
+	leftTerm := self.children[0]
+	if leftTerm.tk.Sym != SymIdentifier {
+		err = fmt.Errorf("left operand of %q must be a variable", self.tk.source)
+		return
+	}
+
+	if v, err = self.children[1].compute(ctx); err == nil {
+		ctx.SetValue(leftTerm.tk.source, v)
+	}
+	return
+}
+
+// init
+func init() {
+	registerTermConstructor(SymEqual, newAssignTerm)
+}

operator-but.go

@@ -0,0 +1,29 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operator-but.go
+package expr
+
+//-------- but term
+
+func newButTerm(tk *Token) (inst *term) {
+	return &term{
+		tk:       *tk,
+		class:    classOperator,
+		kind:     kindUnknown,
+		children: make([]*term, 0, 2),
+		position: posInfix,
+		priority: priBut,
+		evalFunc: evalBut,
+	}
+}
+
+func evalBut(ctx exprContext, self *term) (v any, err error) {
+	_, v, err = self.evalInfix(ctx)
+	return
+}
+
+// init
+func init() {
+	registerTermConstructor(SymKwBut, newButTerm)
+}

parser_test.go

@@ -26,7 +26,7 @@ func TestParser(t *testing.T) {
 	importMathFuncs(ctx)
 
 	// inputs1 := []inputType{
-	// 	{`add(1,2,3)`, int64(6), nil},
+	// 	{`x=2 but x*10`, int64(20), nil},
 	// }
 
 	inputs := []inputType{
@@ -121,7 +121,11 @@ func TestParser(t *testing.T) {
 		/* 89 */ {`~ 2 > 1`, false, nil},
 		/* 90 */ {`~ true && true`, false, nil},
 		/* 91 */ {`~ false || true`, true, nil},
-		/* 92 */ {`~ (false || true)`, false, nil},
+		/* 92 */ {`false but true`, true, nil},
+		/* 93 */ {`2+3 but 5*2`, int64(10), nil},
+		/* 94 */ {`add(1,2) but var2`, "abc", nil},
+		/* 95 */ {`x=2`, int64(2), nil},
+		/* 95 */ {`x=2 but x*10`, int64(20), nil},
 	}
 	succeeded := 0
 	failed := 0
@@ -132,11 +136,7 @@ func TestParser(t *testing.T) {
 		var gotResult any
 		var gotErr error
 
-		if input.wantErr == nil {
-			t.Log(fmt.Sprintf("[+]Test nr %2d -- %q", i+1, input.source))
-		} else {
-			t.Log(fmt.Sprintf("[-]Test nr %2d -- %q", i+1, input.source))
-		}
+		logTest(t, i+1, input.source, input.wantResult, input.wantErr)
 
 		r := strings.NewReader(input.source)
 		scanner := NewScanner(r, DefaultTranslations())
@@ -196,6 +196,7 @@ func TestListParser(t *testing.T) {
 		/*  8 */ {`add([1,[2,2],3,2])`, int64(10), nil},
 		/*  9 */ {`mul([1,4,3.0,2])`, float64(24.0), nil},
 		/* 10 */ {`add([1,"hello"])`, nil, errors.New(`add(): param nr 2 has wrong type string, number expected`)},
+		/* 11 */ {`[a=1,b=2,c=3] but a+b+c`, int64(6), nil},
 		// /*  8 */ {`[int(x)|x=csv("test.csv",1,all(),1)]`, []any{int64(10), int64(40), int64(20)}, nil},
 		// /*  9 */ {`sum(@[int(x)|x=csv("test.csv",1,all(),1)])`, []any{int64(10), int64(40), int64(20)}, nil},
 	}
@@ -209,11 +210,7 @@ func TestListParser(t *testing.T) {
 		var gotResult any
 		var gotErr error
 
-		if input.wantErr == nil {
-			t.Log(fmt.Sprintf("[+]Test nr %2d -- %q  --> %v", i+1, input.source, input.wantResult))
-		} else {
-			t.Log(fmt.Sprintf("[-]Test nr %2d -- %q  --> %v", i+1, input.source, input.wantResult))
-		}
+		logTest(t, i+1, input.source, input.wantResult, input.wantErr)
 
 		r := strings.NewReader(input.source)
 		scanner := NewScanner(r, DefaultTranslations())
@@ -269,3 +266,11 @@ func TestListParser(t *testing.T) {
 	t.Log(fmt.Sprintf("test count: %d, succeeded count: %d, failed count: %d", len(inputs), succeeded, failed))
 
 }
+
+func logTest(t *testing.T, n int, source string, wantResult any, wantErr error) {
+	if wantErr == nil {
+		t.Log(fmt.Sprintf("[+]Test nr %2d -- %q  --> %v", n, source, wantResult))
+	} else {
+		t.Log(fmt.Sprintf("[-]Test nr %2d -- %q  --> %v", n, source, wantErr))
+	}
+}