merge: solved a lot of conflicts caused by an incorect commit removal

README.adoc

@@ -135,6 +135,9 @@ func main() {
 }
 ----
 
+=== Concepts and terminology
+#TODO#
+
 === Data types
 _Expr_ supports numerical, string, relational, boolean expressions, and mixed-type lists.
 
@@ -260,7 +263,15 @@ _Expr_ supports list of mixed-type values, also specified by normal expressions.
 |===
 
 === Variables
-#TODO: variables#
+A variable is an identifier with an assigned value. Variables are stored in the object that implements the _ExprContext_ interface.
+
+.Examples
+[source,go]
+----
+a=1
+x = 5.2 * (9-3)
+x = 1; y = 2*x
+----
 
 === Other operations
 
@@ -346,12 +357,15 @@ The table below shows all supported operators by decreasing priorities.
 .2+|*AND*| [blue]`and` | _Infix_ | _and_ | _boolean_ "and" _boolean_ -> _boolean_
 | [blue]`&&` | _Infix_ | _and_ | _boolean_ "&&" _boolean_ -> _boolean_
 .2+|*OR*| [blue]`or` | _Infix_ | _or_ | _boolean_ "or" _boolean_ -> _boolean_
-| [blue]`||` | _Infix_ | _or_ | _boolean_ "||" _boolean_ -> _boolean_
+| [blue]`\|\|` | _Infix_ | _or_ | _boolean_ "\|\|" _boolean_ -> _boolean_
 .1+|*ASSIGN*| [blue]`=` | _Infix_ | _assignment_ | _identifier_ "=" _any_ -> _any_
 .1+|*BUT*| [blue]`but` | _Infix_ | _but_ | _any_ "but" _any_ -> _any_
 |===
 
 === Functions
+Functions in _Expr_ are very similar to functions in many programming languages.
+
+In _Expr_ functions compute values in a local context (scope) that do not make effects on the calling context. This is the normal behavior. Using the reference operator [blue]`@` it is possibile to export local definition to the calling context.
 
 ==== Function calls
 #TODO: function calls operations#
@@ -359,8 +373,13 @@ The table below shows all supported operators by decreasing priorities.
 ==== Function definitions
 #TODO: function definitions operations#
 
-==== Builtins
+=== Builtins
 #TODO: builtins#
 
+==== Builtin functions
+
+==== [blue]_import()_
+[blue]_import([grey]#<source-file>#)_ loads the multi-expression contained in the specified source and returns its value.
+
 
 

ast.go

@@ -12,6 +12,7 @@ import (
 type Expr interface {
 	Eval(ctx ExprContext) (result any, err error)
 	eval(ctx ExprContext, preset bool) (result any, err error)
+	String() string
 }
 
 //-------- ast
@@ -118,7 +119,7 @@ func (self *ast) eval(ctx ExprContext, preset bool) (result any, err error) {
 		if self.forest != nil {
 			for _, root := range self.forest {
 				if result, err = root.compute(ctx); err == nil {
-					ctx.setVar(control_last_result, result)
+					ctx.setVar(ControlLastResult, result)
 				} else {
 					//err = fmt.Errorf("error in expression nr %d: %v", i+1, err)
 					break

control.go

@@ -5,9 +5,9 @@ import "strings"
 
 // Preset control variables
 const (
-	control_last_result   = "_last"
-	control_bool_shortcut = "_bool_shortcut"
-	control_import_path   = "_import_path"
+	ControlLastResult   = "last"
+	ControlBoolShortcut = "_bool_shortcut"
+	ControlImportPath   = "_import_path"
 )
 
 // Other control variables
@@ -21,23 +21,23 @@ const (
 )
 
 func initDefaultVars(ctx ExprContext) {
-	ctx.setVar(control_bool_shortcut, true)
-	ctx.setVar(control_import_path, init_import_path)
+	ctx.SetVar(ControlBoolShortcut, true)
+	ctx.SetVar(ControlImportPath, init_import_path)
 }
 
 func enable(ctx ExprContext, name string) {
 	if strings.HasPrefix(name, "_") {
-		ctx.setVar(name, true)
+		ctx.SetVar(name, true)
 	} else {
-		ctx.setVar("_"+name, true)
+		ctx.SetVar("_"+name, true)
 	}
 }
 
 func disable(ctx ExprContext, name string) {
 	if strings.HasPrefix(name, "_") {
-		ctx.setVar(name, false)
+		ctx.SetVar(name, false)
 	} else {
-		ctx.setVar("_"+name, false)
+		ctx.SetVar("_"+name, false)
 	}
 }
 

func-import.go

@@ -51,7 +51,7 @@ func addEnvImportDirs(dirList []string) []string {
 }
 
 func addPresetImportDirs(ctx ExprContext, dirList []string) []string {
-	if dirSpec, exists := getControlString(ctx, control_import_path); exists {
+	if dirSpec, exists := getControlString(ctx, ControlImportPath); exists {
 		dirs := strings.Split(dirSpec, ":")
 		if dirList == nil {
 			dirList = dirs
@@ -133,7 +133,7 @@ func doImport(ctx ExprContext, name string, dirList []string, it Iterator) (resu
 	return
 }
 
-func importImportFunc(ctx ExprContext) {
+func ImportImportFunc(ctx ExprContext) {
 	ctx.RegisterFunc("import", &simpleFunctor{f: importFunc}, 1, -1)
 	ctx.RegisterFunc("include", &simpleFunctor{f: includeFunc}, 1, -1)
 }

func-math.go

@@ -101,7 +101,7 @@ func mulFunc(ctx ExprContext, name string, args []any) (result any, err error) {
 	return
 }
 
-func importMathFuncs(ctx ExprContext) {
+func ImportMathFuncs(ctx ExprContext) {
 	ctx.RegisterFunc("add", &simpleFunctor{f: addFunc}, 0, -1)
 	ctx.RegisterFunc("mul", &simpleFunctor{f: mulFunc}, 0, -1)
 }

helpers_test.go

@@ -45,7 +45,6 @@ func TestEvalStringA(t *testing.T) {
 		t.Errorf("Source %q got %v, want %v", source, gotResult, wantResult)
 		t.Errorf("Error: %v", gotErr)
 	}
-	fmt.Println("Hello World!")
 }
 
 func TestEvalString(t *testing.T) {
@@ -76,5 +75,4 @@ func TestEvalString(t *testing.T) {
 		t.Errorf("Source %q got %v, want %v", source, gotResult, wantResult)
 		t.Errorf("Error: %v", gotErr)
 	}
-	fmt.Println("Hello World!")
 }

operand-selector-case.go

@@ -4,7 +4,10 @@
 // operand-selector-case.go
 package expr
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+)
 
 // -------- selector case term
 
@@ -13,6 +16,18 @@ type selectorCase struct {
 	caseExpr   Expr
 }
 
+func (sc *selectorCase) String() string {
+	var sb strings.Builder
+	if sc.filterList != nil {
+		sc.filterList.toString(&sb)
+		sb.WriteByte(' ')
+	}
+	sb.WriteByte('{')
+	sb.WriteString(sc.caseExpr.String())
+	sb.WriteByte('}')
+	return sb.String()
+}
+
 func newSelectorCaseTerm(row, col int, filterList *term, caseExpr Expr) *term {
 	tk := NewValueToken(row, col, SymSelectorCase, "", &selectorCase{filterList: filterList, caseExpr: caseExpr})
 	return &term{

operator-bool.go

@@ -48,7 +48,7 @@ func newAndTerm(tk *Token) (inst *term) {
 }
 
 func evalAnd(ctx ExprContext, self *term) (v any, err error) {
-	if isEnabled(ctx, control_bool_shortcut) {
+	if isEnabled(ctx, ControlBoolShortcut) {
 		v, err = evalAndWithShortcut(ctx, self)
 	} else {
 		v, err = evalAndWithoutShortcut(ctx, self)
@@ -117,7 +117,7 @@ func newOrTerm(tk *Token) (inst *term) {
 }
 
 func evalOr(ctx ExprContext, self *term) (v any, err error) {
-	if isEnabled(ctx, control_bool_shortcut) {
+	if isEnabled(ctx, ControlBoolShortcut) {
 		v, err = evalOrWithShortcut(ctx, self)
 	} else {
 		v, err = evalOrWithoutShortcut(ctx, self)

parser.go

@@ -268,7 +268,7 @@ func (self *parser) parseGeneral(scanner *scanner, allowForest bool, allowVarRef
 			currentTerm, err = tree.addToken2(tk)
 		}
 
-		if currentTerm != nil && currentTerm.parent != nil && currentTerm.parent.tk.Sym != SymSelector {
+		if currentTerm != nil && currentTerm.tk.Sym != SymSelector && currentTerm.parent != nil && currentTerm.parent.tk.Sym != SymSelector {
 			selectorTerm = nil
 
 		}

parser_test.go

@@ -173,8 +173,8 @@ func TestParser(t *testing.T) {
 		ctx := NewSimpleFuncStore()
 		ctx.SetVar("var1", int64(123))
 		ctx.SetVar("var2", "abc")
-		importMathFuncs(ctx)
-		importImportFunc(ctx)
+		ImportMathFuncs(ctx)
+		ImportImportFunc(ctx)
 		parser := NewParser(ctx)
 
 		logTest(t, i+1, input.source, input.wantResult, input.wantErr)
@@ -204,7 +204,7 @@ func TestParser(t *testing.T) {
 		} else {
 			failed++
 			if i+1 == check_env_expr_path {
-				t.Logf(`NOTICE: Test nr %d requires EXPR_PATH environment variable with value "."`, check_env_expr_path)
+				t.Logf(`NOTICE: Test nr %d requires EXPR_PATH="."`, check_env_expr_path)
 			}
 		}
 	}
@@ -249,7 +249,7 @@ func TestListParser(t *testing.T) {
 		ctx := NewSimpleFuncStore()
 		ctx.SetVar("var1", int64(123))
 		ctx.SetVar("var2", "abc")
-		importMathFuncs(ctx)
+		ImportMathFuncs(ctx)
 		parser := NewParser(ctx)
 
 		logTest(t, i+1, input.source, input.wantResult, input.wantErr)

term_test.go

@@ -5,7 +5,6 @@
 package expr
 
 import (
-	"fmt"
 	"testing"
 )
 
@@ -16,7 +15,7 @@ func TestString(t *testing.T) {
 
 	tree := NewAst()
 	if gotErr := tree.addTokens(tk1, tk2, tk3); gotErr == nil {
-		fmt.Println("Tree:", tree)
+		t.Log("Tree:", tree)
 	} else {
 		t.Errorf("err: got <%v>, want <nil>", gotErr)
 	}
@@ -27,7 +26,7 @@ func TestGetRoom(t *testing.T) {
 
 	tree := NewAst()
 	if gotErr := tree.addTokens(tk1); gotErr == nil {
-		fmt.Println("Tree-root room:", tree.root.getRoom())
+		t.Log("Tree-root room:", tree.root.getRoom())
 	} else {
 		t.Errorf("err: got <%v>, want <nil>", gotErr)
 	}
@@ -37,7 +36,7 @@ func TestGetChildrenCount(t *testing.T) {
 
 	tree := NewAst()
 	if gotErr := tree.addTokens(tk1); gotErr == nil {
-		fmt.Println("Tree-root children count:", tree.root.getChildrenCount())
+		t.Log("Tree-root children count:", tree.root.getChildrenCount())
 	} else {
 		t.Errorf("err: got <%v>, want <nil>", gotErr)
 	}

token.go

@@ -27,7 +27,11 @@ func (tk *Token) DevString() string {
 
 func (tk *Token) String() string {
 	if tk.Value != nil {
-		return fmt.Sprintf("%#v", tk.Value)
+		if s, ok := tk.Value.(string); ok {
+			return fmt.Sprintf("%q", s)
+		} else {
+			return fmt.Sprintf("%v", tk.Value)
+		}
 	}
 	return fmt.Sprintf("%s", tk.source)
 }

token_test.go

@@ -5,14 +5,34 @@
 package expr
 
 import (
-	"fmt"
 	"testing"
 )
 
 func TestDevString(t *testing.T) {
-	tk1 := NewValueToken(0, 0, SymInteger, "100", 100)
-	tk2 := NewToken(0, 0, SymPlus, "+")
+	type inputType struct {
+		source     string
+		sym        Symbol
+		value      any
+		wantResult string
+	}
 
-	fmt.Println("Token '100':", tk1.DevString())
-	fmt.Println("Token '+':", tk2.DevString())
+	inputs := []inputType{
+		/*   1 */ {"100", SymInteger, 100, `[55]"100"{100}`},
+		/*   2 */ {"+", SymPlus, nil, `[6]"+"{}`},
+	}
+
+	for i, input := range inputs {
+		var tk *Token
+		if input.value == nil {
+			tk = NewToken(0, 0, input.sym, input.source)
+		} else {
+			tk = NewValueToken(0, 0, input.sym, input.source, input.value)
+		}
+
+		t.Logf("Test nr %2d: %q --> %q", i+1, input.source, input.wantResult)
+
+		if s := tk.DevString(); s != input.wantResult {
+			t.Errorf("wrong token from symbol '+': expected %q, got %q", input.wantResult, s)
+		}
+	}
 }