new string test file

ast.go

@@ -128,6 +128,7 @@ func (self *ast) eval(ctx ExprContext, preset bool) (result any, err error) {
 		}
 		if err == nil {
 			result, err = self.root.compute(ctx)
+			ctx.setVar(ControlLastResult, result)
 		}
 		// } else {
 		// 	err = errors.New("empty expression")

doc/Expr.adoc

@@ -22,15 +22,93 @@ Expressions calculator
 
 toc::[]
 
-#TODO: Work in progress#
+#TODO: Work in progress (last update on 2024/05/10, 06:52 a.m.)#
 
 == Expr
 _Expr_ is a GO package capable of analysing, interpreting and calculating expressions.
 
-
 === Concepts and terminology
 #TODO#
 
+image::expression-diagram.png[]
+
+=== `dev-expr` test tool
+`dev-expr` is a simple program that can be used to evaluate expressions interactively. As its name suggests, it was created for testing purpose. In fact, beyond in additon to the automatic test suite based on the Go test framework, `dev-expr` provides an important aid for quickly testing of new features during their development.
+
+It cat work as a _REPL_, _**R**ead-**E**xecute-**P**rint-**L**oop_, or it can process expression acquired from files or standard input.
+
+The program can be downloaded from https://git.portale-stac.it/go-pkg/-/packages/generic/dev-expr/[dev-expr].
+
+Here are some examples of execution.
+
+.Run `dev-expr` in REPL mode and ask for help
+[source,shell]
+----
+# Assume the expr source directory. Type 'exit' or Ctrl+D to quit the program.
+
+[user]$ tools/expr -- Expressions calculator v1.7.0,2024/05/08 (celestino.amoroso@portale-stac.it)
+	Type help to get the list of command.
+	See also https://git.portale-stac.it/go-pkg/expr/src/branch/main/README.adoc
+
+>>> help
+--- REPL commands:
+        base -- Set the integer output base: 2, 8, 10, or 16
+        exit -- Exit the program
+        help -- Show command list
+          ml -- Enable/Disable multi-line output
+        mods -- List builtin modules
+      source -- Load a file as input
+         tty -- Enable/Disable ansi output <1>
+
+--- Command line options:
+    -b <builtin>       Import builtin modules.
+                       <builtin> can be a list of module names or a glob-pattern.
+                       Use the special value 'all' or the pattern '*' to import all modules.
+    -e <expression>    Evaluate <expression> instead of standard-input
+    -i                 Force REPL operation when all -e occurences have been processed
+    -h, --help, help   Show this help menu
+    -m, --modules      List all builtin modules
+    -p                 Print prefix form
+    -t                 Print tree form <2>
+
+>>> 
+----
+
+<1> Only available for single fraction values
+<2> Work in progress
+
+.REPL examples
+[source,shell]
+----
+[user]$ tools/expr -- Expressions calculator v1.6.1,2024/05/06 (celestino.amoroso@portale-stac.it)
+        Type help to get the list of command.
+        See also https://git.portale-stac.it/go-pkg/expr/src/branch/main/README.adoc
+>>> 2+3
+5
+>>> 2+3*(4-1.5)
+9.5
+>>> 0xFD + 0b1 + 0o1 <1>
+255
+>>> 1|2 + 2|3 <2>
+7|6
+>>> ml <3>
+>>> 1|2 + 2|3
+7
+-
+6
+>>> 1+2 but 5|2+0.5 <4>
+3
+>>> 1+2; 5|2+0.5 <5>
+3
+>>>
+----
+
+<1> Number bases: 0x = hexadecimal, 0o = octal, 0b = binary.
+<2> Fractions: numerator | denominator.
+<3> Activate multi-line output of fractions.
+<4> But operator, see <<_but_operator>>.
+<5> Multi-expression: the same result of the previous single expression but this it is obtained with two separated calculations.
+
 == Data types
 _Expr_ supports numerical, string, relational, boolean expressions, and mixed-type lists.
 
@@ -63,7 +141,44 @@ Numbers can be integers (GO int64) or float (GO float64). In mixed operations in
 
 |=== 
 
-=== String
+=== Fractions
+_Expr_ also supports fractions. Fraction literals are made with two integers separated by a vertical bar `|`.
+
+.Examples
+// [source,go]
+// ----
+`>>>` [blue]`1 | 2` +
+[green]`1|2` +
+`>>>` [blue]`4|6` +
+[green]`2|3` [gray]_Fractions are always reduced to their lowest terms_ +
+`>>>` [blue]`1|2 + 2|3` +
+[green]`7|6` +
+`>>>` [blue]`1|2 * 2|3` +
+[green]`1|3` +
+`>>>` [blue]`1|2 / 1|3` +
+[green]`3|2` +
+`>>>` [blue]`1|2 ./ 1|3` [gray]_Force decimal division_ +
+[green]`1.5` +
+`>>>` [blue]`-1|2` +
+[green]`-1|2` +
+`>>>` [blue]`1|-2` [gray]_Wrong sign specification_ +
+[red]_Eval Error: [1:3] infix operator "|" requires two non-nil operands, got 1_ +
+`>>>` [blue]`1|(-2)` +
+[green]`-1|2`
+// ----
+
+Fractions can be used together with integers and floats in expressions.
+
+`>>>` [blue]`1|2 + 5` +
+[green]`11|2` +
+`>>>` [blue]`4 - 1|2` +
+[green]`7|2` +
+`>>>` [blue]`1.0 + 1|2` +
+[green]`1.5` +
+
+
+
+=== Strings
 Strings are character sequences enclosed between two double quote [blue]`"`. Example: [blue]`"I'm a string"`.
 
 Some arithmetic operators can also be used with strings.
@@ -131,7 +246,7 @@ Currently, boolean operations are evaluated using _short cut evaluation_. This m
 <1> This multi-expression returns _1_ because in the first expression the left value of [blue]`or` is _true_ and as a conseguence its right value is not computed. Therefore the _a_ variable only receives the integer _1_.
 ====
 
-=== List
+=== Lists
 _Expr_ supports list of mixed-type values, also specified by normal expressions.
 
 .List examples
@@ -144,7 +259,6 @@ _Expr_ supports list of mixed-type values, also specified by normal expressions.
 [ [1,"one"], [2,"two"]]     // List of lists
 ----
 
-
 .List operators
 [cols="^2,^2,5,4"]
 |===
@@ -155,6 +269,47 @@ _Expr_ supports list of mixed-type values, also specified by normal expressions.
 | [blue]`-` | _Difference_ | Left list without elements in the right list  | [blue]`[1,2,3] - [2]` _[ [1,3] ]_
 |===
 
+The items of array can be accessed using the dot `.` operator.
+
+.Item access syntax
+[source,bnf]
+----
+<item> ::= <list-expr>"."<index-expr>
+----
+
+.Items of list
+[source,go]
+----
+`>>>` [blue]`[1,2,3].1`
+[green]`2`
+`>>>` [blue]`list=[1,2,3]; list.1`
+[green]`2`
+`>>>` [blue]`["one","two","three"].1`
+[green]`two`
+`>>>` [blue]`list=["one","two","three"]; list.(2-1)`
+[green]`two`
+`>>>` [blue]`list.(-1)`
+[green]`three`
+`>>>` [blue]`list.(-1)`
+[green]`three`
+`>>>` [blue]`list.(10)`
+----
+
+
+
+== Dictionaries
+The _dictionary_ data-type is set of pairs _key/value_. It is also known as _map_ or _associative array_. Dictionary literals are sequences of pairs separated by comma `,`; sequences are enclosed between brace brackets.
+
+.List examples
+[source,go]
+----
+{1:"one", 2:"two"}
+{"one":1, "two": 2}
+{"sum":1+2+3, "prod":1*2*3}
+----
+
+WARNING: Support for dictionaries is still ongoing.
+
 == Variables
 A variable is an identifier with an assigned value. Variables are stored in the object that implements the _ExprContext_ interface.
 
@@ -182,7 +337,7 @@ a=1; b=2; c=3; a+b+c    // returns 6
 ----
 
 === [blue]`but` operator
-[blue]`but` is an infixed operator. Its operands can be any type of expression. It evaluates the left expression first, then the right expression. The value of the right expression is the final result. Examples: [blue]`5 but 2` returns 2, [blue]`x=2*3 but x-1` returns 5.
+[blue]`but` is an infixed operator. Its operands can be expressions of any type. It evaluates the left expression first, then the right expression. The value of the right expression is the final result. Examples: [blue]`5 but 2` returns 2, [blue]`x=2*3 but x-1` returns 5.
 
 [blue]`but` is very similar to [blue]`;`. The only difference is that [blue]`;` can't be used inside parenthesis [blue]`(` and [blue]`)`.
 

formatter.go

@@ -9,6 +9,10 @@ type FmtOpt uint16
 const (
 	TTY FmtOpt = 1 << iota
 	MultiLine
+	Base2
+	Base8
+	Base10
+	Base16
 )
 
 type Formatter interface {

func-base.go

@@ -18,6 +18,42 @@ func isNilFunc(ctx ExprContext, name string, args []any) (result any, err error)
 	return
 }
 
+func isIntFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result = IsInteger(args[0])
+	return
+}
+
+func isFloatFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result = IsFloat(args[0])
+	return
+}
+
+func isBoolFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result = IsBool(args[0])
+	return
+}
+
+func isStringFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result = IsString(args[0])
+	return
+}
+
+func isFractionFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result = IsFract(args[0])
+	return
+}
+
+func isListFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result = IsList(args[0])
+	return
+}
+
+func isDictionaryFunc(ctx ExprContext, name string, args []any) (result any, err error) {
+	result = IsDict(args[0])
+	return
+}
+
+
 func intFunc(ctx ExprContext, name string, args []any) (result any, err error) {
 	if len(args) == 1 {
 		switch v := args[0].(type) {
@@ -50,8 +86,17 @@ func iteratorFunc(ctx ExprContext, name string, args []any) (result any, err err
 }
 
 func ImportBuiltinsFuncs(ctx ExprContext) {
-	ctx.RegisterFunc("isNil", &simpleFunctor{f: isNilFunc}, 1, -1)
-	ctx.RegisterFunc("int", &simpleFunctor{f: intFunc}, 1, -1)
+	ctx.RegisterFunc("isNil", &simpleFunctor{f: isNilFunc}, 1, 1)
+	ctx.RegisterFunc("isInt", &simpleFunctor{f: isIntFunc}, 1, 1)
+	ctx.RegisterFunc("isFloat", &simpleFunctor{f: isFloatFunc}, 1, 1)
+	ctx.RegisterFunc("isBool", &simpleFunctor{f: isBoolFunc}, 1, 1)
+	ctx.RegisterFunc("isString", &simpleFunctor{f: isStringFunc}, 1, 1)
+	ctx.RegisterFunc("isFraction", &simpleFunctor{f: isFractionFunc}, 1, 1)
+	ctx.RegisterFunc("isFract", &simpleFunctor{f: isFractionFunc}, 1, 1)
+	ctx.RegisterFunc("isList", &simpleFunctor{f: isListFunc}, 1, 1)
+	ctx.RegisterFunc("isDictionary", &simpleFunctor{f: isDictionaryFunc}, 1, 1)
+	ctx.RegisterFunc("isDict", &simpleFunctor{f: isDictionaryFunc}, 1, 1)
+	ctx.RegisterFunc("int", &simpleFunctor{f: intFunc}, 1, 1)
 }
 
 func init() {

func-import.go

@@ -35,7 +35,7 @@ func importGeneral(ctx ExprContext, name string, args []any) (result any, err er
 }
 
 func checkStringParamExpected(funcName string, paramValue any, paramPos int) (err error) {
-	if !(isString(paramValue) /*|| isList(paramValue)*/) {
+	if !(IsString(paramValue) /*|| isList(paramValue)*/) {
 		err = fmt.Errorf("%s(): param nr %d has wrong type %T, string expected", funcName, paramPos+1, paramValue)
 	}
 	return

func-math.go

@@ -10,7 +10,7 @@ import (
 )
 
 func checkNumberParamExpected(funcName string, paramValue any, paramPos, level, subPos int) (err error) {
-	if !(isNumber(paramValue) || isFraction(paramValue)) /*|| isList(paramValue)*/ {
+	if !(IsNumber(paramValue) || isFraction(paramValue)) /*|| isList(paramValue)*/ {
 		err = fmt.Errorf("%s(): param nr %d (%d in %d) has wrong type %T, number expected",
 			funcName, paramPos+1, subPos+1, level, paramValue)
 	}
@@ -45,7 +45,7 @@ func doAdd(ctx ExprContext, name string, it Iterator, count, level int) (result
 		count++
 
 		if !sumAsFloat {
-			if isFloat(v) {
+			if IsFloat(v) {
 				sumAsFloat = true
 				if sumAsFract {
 					floatSum = fractSum.toFloat()
@@ -120,7 +120,7 @@ func doMul(ctx ExprContext, name string, it Iterator, count, level int) (result
 		count++
 
 		if !mulAsFloat {
-			if isFloat(v) {
+			if IsFloat(v) {
 				mulAsFloat = true
 				if mulAsFract {
 					floatProd = fractProd.toFloat()

funcs_test.go

@@ -20,7 +20,7 @@ func TestFuncs(t *testing.T) {
 		/*   7 */ {`int(3.9)`, int64(3), nil},
 		/*   8 */ {`int("432")`, int64(432), nil},
 		/*   9 */ {`int("1.5")`, nil, errors.New(`strconv.Atoi: parsing "1.5": invalid syntax`)},
-		/*  10 */ {`int("432", 4)`, nil, errors.New(`int() requires exactly one param`)},
+		/*  10 */ {`int("432", 4)`, nil, errors.New(`too much params -- expected 1, got 2`)},
 		/*  11 */ {`int(nil)`, nil, errors.New(`int() can't convert <nil> to int`)},
 		/*  12 */ {`two=func(){2}; two()`, int64(2), nil},
 		/*  13 */ {`double=func(x) {2*x}; (double(3))`, int64(6), nil},
@@ -54,9 +54,15 @@ func TestFuncs(t *testing.T) {
 		/*  41 */ {`builtin "string"; endsWithStr("0123456789", "xyz", "789")`, true, nil},
 		/*  42 */ {`builtin "string"; endsWithStr("0123456789", "xyz", "0125")`, false, nil},
 		/*  43 */ {`builtin "string"; endsWithStr("0123456789")`, nil, errors.New(`too few params -- expected 2 or more, got 1`)},
-		/*  44 */ {`builtin "string"; splitStr("one-two-three", "-", )`, newListA("one","two","three"), nil},
-		/*  45 */ {`["a", "b", "c"]`, newListA("a","b","c"), nil},
-		/*  46 */ {`["a", "b", "c"]`, newList([]any{"a","b","c"}), nil},
+		/*  44 */ {`builtin "string"; splitStr("one-two-three", "-", )`, newListA("one", "two", "three"), nil},
+		/*  45 */ {`isInt(2+1)`, true, nil},
+		/*  46 */ {`isInt(3.1)`, false, nil},
+		/*  46 */ {`isFloat(3.1)`, true, nil},
+		/*  47 */ {`isString("3.1")`, true, nil},
+		/*  48 */ {`isString("3" + 1)`, true, nil},
+		/*  49 */ {`isList(["3",  1])`, true, nil},
+		/*  50 */ {`isDict({"a":"3",  "b":1})`, true, nil},
+		/*  51 */ {`isFract(3|1)`, true, nil},
 	}
 
 	t.Setenv("EXPR_PATH", ".")

list_test.go

@@ -20,22 +20,25 @@ func TestListParser(t *testing.T) {
 	}
 
 	inputs := []inputType{
-		/*  1 */ {`[]`, []any{}, nil},
-		/*  2 */ {`[1,2,3]`, []any{int64(1), int64(2), int64(3)}, nil},
-		/*  3 */ {`[1,2,"hello"]`, []any{int64(1), int64(2), "hello"}, nil},
-		/*  4 */ {`[1+2, not true, "hello"]`, []any{int64(3), false, "hello"}, nil},
-		/*  5 */ {`[1,2]+[3]`, []any{int64(1), int64(2), int64(3)}, nil},
-		/*  6 */ {`[1,4,3,2]-[3]`, []any{int64(1), int64(4), int64(2)}, nil},
-		/*  7 */ {`add([1,4,3,2])`, int64(10), nil},
-		/*  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 (2 in 1) has wrong type string, number expected`)},
-		/* 11 */ {`[a=1,b=2,c=3] but a+b+c`, int64(6), nil},
-		/* 12 */ {`[1,2,3] << 2+2`, []any{int64(1), int64(2), int64(3), int64(4)}, nil},
-		/* 13 */ {`2-1 >> [2,3]`, []any{int64(1), int64(2), int64(3)}, nil},
-		/* 14 */ {`[1,2,3].1`, int64(2), nil},
-		/* 15 */ {`ls=[1,2,3] but ls.1`, int64(2), nil},
-		/* 16 */ {`ls=[1,2,3] but ls.(-1)`, int64(3), nil},
+		/*   1 */ {`[]`, []any{}, nil},
+		/*   2 */ {`[1,2,3]`, []any{int64(1), int64(2), int64(3)}, nil},
+		/*   3 */ {`[1,2,"hello"]`, []any{int64(1), int64(2), "hello"}, nil},
+		/*   4 */ {`[1+2, not true, "hello"]`, []any{int64(3), false, "hello"}, nil},
+		/*   5 */ {`[1,2]+[3]`, []any{int64(1), int64(2), int64(3)}, nil},
+		/*   6 */ {`[1,4,3,2]-[3]`, []any{int64(1), int64(4), int64(2)}, nil},
+		/*   7 */ {`add([1,4,3,2])`, int64(10), nil},
+		/*   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 (2 in 1) has wrong type string, number expected`)},
+		/*  11 */ {`[a=1,b=2,c=3] but a+b+c`, int64(6), nil},
+		/*  12 */ {`[1,2,3] << 2+2`, []any{int64(1), int64(2), int64(3), int64(4)}, nil},
+		/*  13 */ {`2-1 >> [2,3]`, []any{int64(1), int64(2), int64(3)}, nil},
+		/*  14 */ {`[1,2,3].1`, int64(2), nil},
+		/*  15 */ {`ls=[1,2,3] but ls.1`, int64(2), nil},
+		/*  16 */ {`ls=[1,2,3] but ls.(-1)`, int64(3), nil},
+		/*  17 */ {`list=["one","two","three"]; list.10`, nil, errors.New(`[1:36] index 10 out of bounds`)},
+		/*  18 */ {`["a", "b", "c"]`, newListA("a", "b", "c"), nil},
+		/*  19 */ {`["a", "b", "c"]`, newList([]any{"a", "b", "c"}), 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},

operator-assign.go

@@ -1,5 +1,5 @@
 // Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
-// All rights reserved.
+// All rights reserightChilded.
 
 // operator-assign.go
 package expr
@@ -27,11 +27,17 @@ func evalAssign(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if v, err = self.children[1].compute(ctx); err == nil {
-		if functor, ok := v.(Functor); ok {
-			var minArgs, maxArgs int = 0, 0
+	rightChild := self.children[1]
 
-			if funcDef, ok := functor.(*funcDefFunctor); ok {
+	if v, err = rightChild.compute(ctx); err == nil {
+		if functor, ok := v.(Functor); ok {
+			var minArgs, maxArgs int = 0, -1
+
+			funcName := rightChild.source()
+			if info, exists := ctx.GetFuncInfo(funcName); exists {
+				minArgs = info.MinArgs()
+				maxArgs = info.MaxArgs()
+			} else if funcDef, ok := functor.(*funcDefFunctor); ok {
 				l := len(funcDef.params)
 				minArgs = l
 				maxArgs = l

operator-builtin.go

@@ -26,7 +26,7 @@ func evalBuiltin(ctx ExprContext, self *term) (v any, err error) {
 	}
 
 	count := 0
-	if isString(childValue) {
+	if IsString(childValue) {
 		module, _ := childValue.(string)
 		count, err = ImportInContextByGlobPattern(ctx, module)
 	} else {

operator-dot.go

@@ -22,10 +22,11 @@ func verifyIndex(ctx ExprContext, indexTerm *term, maxValue int) (index int, err
 	var indexValue any
 	if indexValue, err = indexTerm.compute(ctx); err == nil {
 		if v, err = indexTerm.toInt(indexValue, "index expression value must be integer"); err == nil {
+			if v < 0 && v >= -maxValue {
+				v = maxValue + v
+			}
 			if v >= 0 && v < maxValue {
 				index = v
-			} else if index >= -maxValue {
-				index = maxValue + v
 			} else {
 				err = indexTerm.Errorf("index %d out of bounds", v)
 			}
@@ -56,7 +57,7 @@ func evalDot(ctx ExprContext, self *term) (v any, err error) {
 	case string:
 		var index int
 		if index, err = verifyIndex(ctx, indexTerm, len(unboxedValue)); err == nil {
-			v = unboxedValue[index]
+			v = string(unboxedValue[index])
 		}
 	case map[any]any:
 		var ok bool

operator-fact.go

@@ -25,7 +25,7 @@ func evalFact(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isInteger(leftValue) {
+	if IsInteger(leftValue) {
 		if i, _ := leftValue.(int64); i >= 0 {
 			f := int64(1)
 			for k := int64(1); k <= i; k++ {

operator-include.go

@@ -24,7 +24,7 @@ func evalInclude(ctx ExprContext, self *term) (v any, err error) {
 	}
 
 	count := 0
-	if isList(childValue) {
+	if IsList(childValue) {
 		list, _ := childValue.([]any)
 		for i, filePathSpec := range list {
 			if filePath, ok := filePathSpec.(string); ok {
@@ -39,7 +39,7 @@ func evalInclude(ctx ExprContext, self *term) (v any, err error) {
 				break
 			}
 		}
-	} else if isString(childValue) {
+	} else if IsString(childValue) {
 		filePath, _ := childValue.(string)
 		v, err = EvalFile(ctx, filePath)
 	} else {

operator-insert.go

@@ -33,7 +33,7 @@ func evalInsert(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isList(rightValue) {
+	if IsList(rightValue) {
 		list, _ := rightValue.(*ListType)
 		newList := append(ListType{leftValue}, *list...)
 		v = &newList
@@ -50,7 +50,7 @@ func evalAppend(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isList(leftValue) {
+	if IsList(leftValue) {
 		list, _ := leftValue.(*ListType)
 		newList := append(*list, rightValue)
 		v = &newList

operator-length.go

@@ -23,10 +23,10 @@ func evalLength(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isList(childValue) {
+	if IsList(childValue) {
 		list, _ := childValue.([]any)
 		v = int64(len(list))
-	} else if isString(childValue) {
+	} else if IsString(childValue) {
 		s, _ := childValue.(string)
 		v = int64(len(s))
 	} else if it, ok := childValue.(Iterator); ok {

operator-post-inc.go

@@ -25,7 +25,7 @@ func evalPostInc(ctx ExprContext, self *term) (v any, err error) {
 
 	if it, ok := childValue.(Iterator); ok {
 		v, err = it.Next()
-	} else if isInteger(childValue) && self.children[0].symbol() == SymIdentifier {
+	} else if IsInteger(childValue) && self.children[0].symbol() == SymIdentifier {
 		v = childValue
 		i, _ := childValue.(int64)
 		ctx.SetVar(self.children[0].source(), i+1)

operator-prod.go

@@ -30,20 +30,20 @@ func evalMultiply(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isString(leftValue) && isInteger(rightValue) {
+	if IsString(leftValue) && IsInteger(rightValue) {
 		s, _ := leftValue.(string)
 		n, _ := rightValue.(int64)
 		v = strings.Repeat(s, int(n))
-	} else if isNumber(leftValue) && isNumber(rightValue) {
-		if isFloat(leftValue) || isFloat(rightValue) {
+	} else if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
+		if IsFloat(leftValue) || IsFloat(rightValue) {
 			v = numAsFloat(leftValue) * numAsFloat(rightValue)
+		} else if isFraction(leftValue) || isFraction(rightValue) {
+			v, err = mulAnyFract(leftValue, rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			rightInt, _ := rightValue.(int64)
 			v = leftInt * rightInt
 		}
-	} else if isFraction(leftValue) || isFraction(rightValue) {
-		v, err = mulAnyFract(leftValue, rightValue)
 	} else {
 		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -71,14 +71,16 @@ func evalDivide(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isNumber(leftValue) && isNumber(rightValue) {
-		if isFloat(leftValue) || isFloat(rightValue) {
+	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
+		if IsFloat(leftValue) || IsFloat(rightValue) {
 			d := numAsFloat(rightValue)
 			if d == 0.0 {
 				err = errors.New("division by zero")
 			} else {
 				v = numAsFloat(leftValue) / d
 			}
+		} else if isFraction(leftValue) || isFraction(rightValue) {
+			v, err = divAnyFract(leftValue, rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			if rightInt, _ := rightValue.(int64); rightInt == 0 {
@@ -87,8 +89,6 @@ func evalDivide(ctx ExprContext, self *term) (v any, err error) {
 				v = leftInt / rightInt
 			}
 		}
-	} else if isFraction(leftValue) || isFraction(rightValue) {
-		v, err = divAnyFract(leftValue, rightValue)
 	} else {
 		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -114,7 +114,7 @@ func evalDivideAsFloat(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isNumber(leftValue) && isNumber(rightValue) {
+	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
 		d := numAsFloat(rightValue)
 		if d == 0.0 {
 			err = errors.New("division by zero")
@@ -148,7 +148,7 @@ func evalReminder(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isInteger(leftValue) && isInteger(rightValue) {
+	if IsInteger(leftValue) && IsInteger(rightValue) {
 		rightInt, _ := rightValue.(int64)
 		if rightInt == 0 {
 			err = errors.New("division by zero")

operator-rel.go

@@ -25,15 +25,15 @@ func evalEqual(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isNumber(leftValue) && isNumber(rightValue) {
-		if isInteger(leftValue) && isInteger(rightValue) {
+	if IsNumber(leftValue) && IsNumber(rightValue) {
+		if IsInteger(leftValue) && IsInteger(rightValue) {
 			li, _ := leftValue.(int64)
 			ri, _ := rightValue.(int64)
 			v = li == ri
 		} else {
 			v = numAsFloat(leftValue) == numAsFloat(rightValue)
 		}
-	} else if isString(leftValue) && isString(rightValue) {
+	} else if IsString(leftValue) && IsString(rightValue) {
 		ls, _ := leftValue.(string)
 		rs, _ := rightValue.(string)
 		v = ls == rs
@@ -111,15 +111,15 @@ func evalLess(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isNumber(leftValue) && isNumber(rightValue) {
-		if isInteger(leftValue) && isInteger(rightValue) {
+	if IsNumber(leftValue) && IsNumber(rightValue) {
+		if IsInteger(leftValue) && IsInteger(rightValue) {
 			li, _ := leftValue.(int64)
 			ri, _ := rightValue.(int64)
 			v = li < ri
 		} else {
 			v = numAsFloat(leftValue) < numAsFloat(rightValue)
 		}
-	} else if isString(leftValue) && isString(rightValue) {
+	} else if IsString(leftValue) && IsString(rightValue) {
 		ls, _ := leftValue.(string)
 		rs, _ := rightValue.(string)
 		v = ls < rs
@@ -148,15 +148,15 @@ func evalLessEqual(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isNumber(leftValue) && isNumber(rightValue) {
-		if isInteger(leftValue) && isInteger(rightValue) {
+	if IsNumber(leftValue) && IsNumber(rightValue) {
+		if IsInteger(leftValue) && IsInteger(rightValue) {
 			li, _ := leftValue.(int64)
 			ri, _ := rightValue.(int64)
 			v = li <= ri
 		} else {
 			v = numAsFloat(leftValue) <= numAsFloat(rightValue)
 		}
-	} else if isString(leftValue) && isString(rightValue) {
+	} else if IsString(leftValue) && IsString(rightValue) {
 		ls, _ := leftValue.(string)
 		rs, _ := rightValue.(string)
 		v = ls <= rs

operator-sign.go

@@ -35,14 +35,14 @@ func evalSign(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isFloat(rightValue) {
+	if IsFloat(rightValue) {
 		if self.tk.Sym == SymChangeSign {
 			f, _ := rightValue.(float64)
 			v = -f
 		} else {
 			v = rightValue
 		}
-	} else if isInteger(rightValue) {
+	} else if IsInteger(rightValue) {
 		if self.tk.Sym == SymChangeSign {
 			i, _ := rightValue.(int64)
 			v = -i

operator-sum.go

@@ -28,17 +28,17 @@ func evalPlus(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if (isString(leftValue) && isNumberString(rightValue)) || (isString(rightValue) && isNumberString(leftValue)) {
+	if (IsString(leftValue) && isNumberString(rightValue)) || (IsString(rightValue) && isNumberString(leftValue)) {
 		v = fmt.Sprintf("%v%v", leftValue, rightValue)
-	} else if isNumber(leftValue) && isNumber(rightValue) {
-		if isFloat(leftValue) || isFloat(rightValue) {
+	} else if IsNumber(leftValue) && IsNumber(rightValue) {
+		if IsFloat(leftValue) || IsFloat(rightValue) {
 			v = numAsFloat(leftValue) + numAsFloat(rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			rightInt, _ := rightValue.(int64)
 			v = leftInt + rightInt
 		}
-	} else if isList(leftValue) || isList(rightValue) {
+	} else if IsList(leftValue) || IsList(rightValue) {
 		var leftList, rightList *ListType
 		var ok bool
 		if leftList, ok = leftValue.(*ListType); !ok {
@@ -56,7 +56,11 @@ func evalPlus(ctx ExprContext, self *term) (v any, err error) {
 		}
 		v = &sumList
 	} else if isFraction(leftValue) || isFraction(rightValue) {
-		v, err = sumAnyFract(leftValue, rightValue)
+		if IsFloat(leftValue) || IsFloat(rightValue) {
+			v = numAsFloat(leftValue) + numAsFloat(rightValue)
+		} else {
+			v, err = sumAnyFract(leftValue, rightValue)
+		}
 	} else {
 		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -82,15 +86,17 @@ func evalMinus(ctx ExprContext, self *term) (v any, err error) {
 		return
 	}
 
-	if isNumber(leftValue) && isNumber(rightValue) {
-		if isFloat(leftValue) || isFloat(rightValue) {
+	if isNumOrFract(leftValue) && isNumOrFract(rightValue) {
+		if IsFloat(leftValue) || IsFloat(rightValue) {
 			v = numAsFloat(leftValue) - numAsFloat(rightValue)
+		} else if isFraction(leftValue) || isFraction(rightValue) {
+			v, err = subAnyFract(leftValue, rightValue)
 		} else {
 			leftInt, _ := leftValue.(int64)
 			rightInt, _ := rightValue.(int64)
 			v = leftInt - rightInt
 		}
-	} else if isList(leftValue) && isList(rightValue) {
+	} else if IsList(leftValue) && IsList(rightValue) {
 		leftList, _ := leftValue.(*ListType)
 		rightList, _ := rightValue.(*ListType)
 		diffList := make(ListType, 0, len(*leftList)-len(*rightList))
@@ -100,8 +106,6 @@ func evalMinus(ctx ExprContext, self *term) (v any, err error) {
 			}
 		}
 		v = &diffList
-	} else if isFraction(leftValue) || isFraction(rightValue) {
-		v, err = subAnyFract(leftValue, rightValue)
 	} else {
 		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}

parser_test.go

@@ -35,10 +35,10 @@ func TestGeneralParser(t *testing.T) {
 		/*  14 */ {`not true`, false, nil},
 		/*  15 */ {`true and false`, false, nil},
 		/*  16 */ {`true or false`, true, nil},
-		/*  17 */ {`"uno" + "due"`, `unodue`, nil},
-		/*  18 */ {`"uno" + 2`, `uno2`, nil},
-		/*  19 */ {`"uno" + (2+1)`, `uno3`, nil},
-		/*  20 */ {`"uno" * (2+1)`, `unounouno`, nil},
+		/*  *17 */ {`"uno" + "due"`, `unodue`, nil},
+		/*  *18 */ {`"uno" + 2`, `uno2`, nil},
+		/*  *19 */ {`"uno" + (2+1)`, `uno3`, nil},
+		/*  *20 */ {`"uno" * (2+1)`, `unounouno`, nil},
 		/*  21 */ {"1", int64(1), nil},
 		/*  22 */ {"1.5", float64(1.5), nil},
 		/*  23 */ {"1.5*2", float64(3.0), nil},
@@ -157,6 +157,7 @@ func TestGeneralParser(t *testing.T) {
 		/* 136 */ {`builtin "math.arith"; mul(1|2, 1.0, 2)`, float64(1.0), nil},
 		/* 137 */ {`builtin "os.file"`, int64(1), nil},
 		/* 138 */ {`v=10; v++; v`, int64(11), nil},
+		/* 139 */ {`1+1|2+0.5`, float64(2), nil},
 	}
 
 	// t.Setenv("EXPR_PATH", ".")
@@ -176,7 +177,7 @@ func parserTest(t *testing.T, section string, inputs []inputType) {
 		ctx := NewSimpleFuncStore()
 		parser := NewParser(ctx)
 
-		logTest(t, i+1, "Iterator", input.source, input.wantResult, input.wantErr)
+		logTest(t, i+1, section, input.source, input.wantResult, input.wantErr)
 
 		r := strings.NewReader(input.source)
 		scanner := NewScanner(r, DefaultTranslations())

strings_test.go

@@ -0,0 +1,21 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// strings_test.go
+package expr
+
+import (
+	"testing"
+)
+
+func TestStringsParser(t *testing.T) {
+	inputs := []inputType{
+		/*  1 */ {`"uno" + "due"`, `unodue`, nil},
+		/*  2 */ {`"uno" + 2`, `uno2`, nil},
+		/*  3 */ {`"uno" + (2+1)`, `uno3`, nil},
+		/*  4 */ {`"uno" * (2+1)`, `unounouno`, nil},
+		/*  5 */ {`"abc".1`, `b`, nil},
+		/*  5 */ {`#"abc"`, int64(3), nil},
+	}
+	parserTest(t, "String", inputs)
+}

utils.go

@@ -9,37 +9,51 @@ import (
 	"reflect"
 )
 
-func isString(v any) (ok bool) {
+func IsString(v any) (ok bool) {
 	_, ok = v.(string)
 	return ok
 }
 
-func isInteger(v any) (ok bool) {
+func IsInteger(v any) (ok bool) {
 	_, ok = v.(int64)
 	return ok
 }
 
-func isFloat(v any) (ok bool) {
+func IsFloat(v any) (ok bool) {
 	_, ok = v.(float64)
 	return ok
 }
 
-func isList(v any) (ok bool) {
+func IsBool(v any) (ok bool) {
+	_, ok = v.(bool)
+	return ok
+}
+
+func IsList(v any) (ok bool) {
 	_, ok = v.(*ListType)
 	return ok
 }
 
-func isDict(v any) (ok bool) {
+func IsDict(v any) (ok bool) {
 	_, ok = v.(map[any]any)
 	return ok
 }
 
-func isNumber(v any) (ok bool) {
-	return isFloat(v) || isInteger(v)
+func IsFract(v any) (ok bool) {
+	_, ok = v.(*fraction)
+	return ok
+}
+
+func IsNumber(v any) (ok bool) {
+	return IsFloat(v) || IsInteger(v)
+}
+
+func isNumOrFract(v any) (ok bool) {
+	return IsFloat(v) || IsInteger(v) || isFraction(v)
 }
 
 func isNumberString(v any) (ok bool) {
-	return isString(v) || isNumber(v)
+	return IsString(v) || IsNumber(v)
 }
 
 func isFunctor(v any) (ok bool) {