Edited according to preious commit

with the new operators '<+' and '+>' respectively.
'<<' and '>>' are now used only for left and right binary shit
respectively. Further, their priority has been increased moving them to
a higher priority than that of the assignment operator.

builtin-base.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"math"
 	"strconv"
+	"strings"
 )
 
 const (
@@ -188,6 +189,30 @@ func fractFunc(ctx ExprContext, name string, args map[string]any) (result any, e
 // 	return
 // }
 
+func evalFunc(ctx ExprContext, name string, args map[string]any) (result any, err error) {
+	if source, ok := args[ParamSource].(string); ok {
+		var expr Expr
+
+		parser := NewParser()
+		if ctx == nil {
+			ctx = NewSimpleStore()
+		}
+
+		r := strings.NewReader(source)
+		scanner := NewScanner(r, DefaultTranslations())
+
+		if expr, err = parser.Parse(scanner); err == nil {
+			CtrlEnable(ctx, control_export_all)
+			result, err = expr.Eval(ctx)
+		}
+	} else {
+		err = ErrWrongParamType(name, ParamSource, TypeString, args[ParamSource])
+	}
+	return
+}
+
+//// import
+
 func ImportBuiltinsFuncs(ctx ExprContext) {
 	anyParams := []ExprFuncParam{
 		NewFuncParam(ParamValue),
@@ -211,6 +236,10 @@ func ImportBuiltinsFuncs(ctx ExprContext) {
 		NewFuncParam(ParamValue),
 		NewFuncParamFlagDef(ParamDenominator, PfDefault, int64(1)),
 	})
+
+	ctx.RegisterFunc("eval", NewGolangFunctor(evalFunc), TypeAny, []ExprFuncParam{
+		NewFuncParam(ParamSource),
+	})
 }
 
 func init() {

common-errors.go

@@ -55,8 +55,25 @@ func ErrInvalidParameterValue(funcName, paramName string, paramValue any) error
 	return fmt.Errorf("%s(): invalid value %s (%v) for parameter %q", funcName, TypeName(paramValue), paramValue, paramName)
 }
 
+func undefArticle(s string) (article string) {
+	if len(s) > 0 && strings.Contains("aeiou", s[0:1]) {
+		article = "an"
+	} else {
+		article = "a"
+	}
+	return
+}
+
+func prependUndefArticle(s string) (result string) {
+	return undefArticle(s) + " " + s
+}
+
 func ErrWrongParamType(funcName, paramName, paramType string, paramValue any) error {
-	return fmt.Errorf("%s(): the %q parameter must be a %s, got a %s (%v)", funcName, paramName, paramType, TypeName(paramValue), paramValue)
+	var artWantType, artGotType string
+	gotType := TypeName(paramValue)
+	artGotType = prependUndefArticle(gotType)
+	artWantType = prependUndefArticle(paramType)
+	return fmt.Errorf("%s(): the %q parameter must be %s, got %s (%v)", funcName, paramName, artWantType, artGotType, paramValue)
 }
 
 func ErrUnknownParam(funcName, paramName string) error {

context-helpers.go

@@ -29,7 +29,7 @@ func exportObjects(destCtx, sourceCtx ExprContext) {
 	exportAll := CtrlIsEnabled(sourceCtx, control_export_all)
 	// fmt.Printf("Exporting from sourceCtx [%p] to destCtx [%p] -- exportAll=%t\n", sourceCtx, destCtx, exportAll)
 	// Export variables
-	for _, refName := range sourceCtx.EnumVars(func(name string) bool { return exportAll || name[0] == '@' }) {
+	for _, refName := range sourceCtx.EnumVars(func(name string) bool { return (exportAll || name[0] == '@') && !(name[0] == '_') }) {
 		// fmt.Printf("\tExporting %q\n", refName)
 		refValue, _ := sourceCtx.GetVar(refName)
 		exportVar(destCtx, refName, refValue)

doc/Expr.adoc

@@ -127,22 +127,22 @@ dev-expr -- Expressions calculator v1.10.0(build 14),2024/06/17 (celestino.amoro
 9.5
 >>> 0xFD + 0b1 + 0o1 <1>
 255
->>> 1|2 + 2|3 <2>
+>>> 1:2 + 2:3 <2>
-7|6
+7:6
 >>> ml <3>
->>> 1|2 + 2|3
+>>> 1:2 + 2:3
 7
 -
 6
->>> 4+2 but 5|2+0.5 <4>
+>>> 4+2 but 5:2+0.5 <4>
 3
->>> 4+2; 5|2+0.5 <5>
+>>> 4+2; 5:2+0.5 <5>
 3
 >>>
 ----
 
 <1> Number bases: 0x = _hexadecimal_, 0o = _octal_, 0b = _binary_.
-<2> Fractions: _numerator_ | _denominator_.
+<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.
@@ -236,11 +236,11 @@ _dec-seq_ = _see-integer-literal-syntax_
 |===
 
 ==== Fractions
-_Expr_ also supports fractions. Fraction literals are made with two integers separated by a vertical bar `|`.
+_Expr_ also supports fractions. Fraction literals are made with two integers separated by a colon character `:`.
 
 .Fraction literal syntax
 ====
-*_fraction_* = [__sign__] (_num-den-spec_ | _float-spec_) +
+*_fraction_* = [__sign__] (_num-den-spec_ "**:**" _float-spec_) +
 _sign_ = "**+**" | "**-**" +
 _num-den-spec_ = _digit-seq_ "**|**" _digit-seq_ +
 _float-spec_ = _dec-seq_ "**.**" [_dec-seq_] "**(**" _dec-seq_ "**)**" +
@@ -249,44 +249,44 @@ _digit-seq_ = _see-integer-literal-syntax_
 ====
 
 .Examples
-`>>>` [blue]`1 | 2` +
+`>>>` [blue]`1 : 2` +
-[green]`1|2`
+[green]`1:2`
 
-`>>>` [blue]`4|6`  [gray]_// Fractions are always reduced to their lowest terms_ +
+`>>>` [blue]`4:6`  [gray]_// Fractions are always reduced to their lowest terms_ +
-[green]`2|3`
+[green]`2:3`
 
-`>>>` [blue]`1|2 + 2|3` +
+`>>>` [blue]`1:2 + 2:3` +
-[green]`7|6`
+[green]`7:6`
 
-`>>>` [blue]`1|2 * 2|3` +
+`>>>` [blue]`1:2 * 2:3` +
-[green]`1|3`
+[green]`1:3`
 
-`>>>` [blue]`1|2 / 1|3` +
+`>>>` [blue]`1:2 / 1:3` +
-[green]`3|2`
+[green]`3:2`
 
-`>>>` [blue]`1|2 ./ 1|3` [gray]_// Force decimal division_ +
+`>>>` [blue]`1:2 ./ 1:3` [gray]_// Force decimal division_ +
 [green]`1.5`
 
-`>>>` [blue]`-1|2` +
+`>>>` [blue]`-1:2` +
-[green]`-1|2`
+[green]`-1:2`
 
-`>>>` [blue]`1|-2` [gray]_// Invalid sign specification_ +
+`>>>` [blue]`1:-2` [gray]_// Invalid sign specification_ +
-[red]_Eval Error: [1:3] infix operator "|" requires two non-nil operands, got 1_
+[red]_Eval Error: [1:3] infix operator ":" requires two non-nil operands, got 1_
 
-`>>>` [blue]`1|(-2)` +
+`>>>` [blue]`1:(-2)` +
-[green]`-1|2`
+[green]`-1:2`
 
 
 Fractions can be used together with integers and floats in expressions.
 
 .Examples
-`>>>` [blue]`1|2 + 5` +
+`>>>` [blue]`1:2 + 5` +
-[green]`11|2`
+[green]`11:2`
 
-`>>>` [blue]`4 - 1|2` +
+`>>>` [blue]`4 - 1:2` +
-[green]`7|2`
+[green]`7:2`
 
-`>>>` [blue]`1.0 + 1|2` +
+`>>>` [blue]`1.0 + 1:2` +
 [green]`1.5`
 
 
@@ -439,8 +439,8 @@ _non-empty-list_ = "**[**" _any-value_ {"**,**" _any-value_} "**]**" +
 
 | [blue]`+` | _Join_ | Joins two lists | [blue]`[1,2] + [3]` -> _[1,2,3]_
 | [blue]`-` | _Difference_ | Left list without elements in the right list  | [blue]`[1,2,3] - [2]` -> _[1,3]_
-| [blue]`>>` | _Front insertion_ | Insert an item in front | [blue]`0 >> [1,2]` -> _[0,1,2]_
+| [blue]`+>` | _Front insertion_ | Insert an item in front | [blue]`0 +> [1,2]` -> _[0,1,2]_
-| [blue]`<<` | _Back insertion_ | Insert an item at end | [blue]`[1,2] << 3` -> _[1,2,3]_
+| [blue]`<+` | _Back insertion_ | Insert an item at end | [blue]`[1,2] <+ 3` -> _[1,2,3]_
 | [blue]`[]` | _Item at index_ | Item at given position | [blue]`[1,2,3][1]` -> _2_
 | [blue]`in` | _Item in list_ | True if item is in list | [blue]`2 in [1,2,3]` -> _true_ +
 [blue]`6 in [1,2,3]` -> _false_
@@ -735,7 +735,7 @@ NOTE: These operators have a high priority, in particular higher than the operat
 The table below shows all supported operators by decreasing priorities.
 
 .Operators priorities
-[cols="^2,^2,^2,^5,^6"]
+[cols="^3,^2,^2,^5,^6"]
 |===
 | Priority | Operators     | Position | Operation | Operands and results
 
@@ -753,7 +753,7 @@ The table below shows all supported operators by decreasing priorities.
 | [blue]`#` | _Prefix_ | _Size-of_ | `#` _iterator_ -> _integer_
 .2+|*SELECT*| [blue]`? : ::` | _Multi-Infix_ | _Case-Selector_ | _any-expr_ `?` _case-list_ _case-expr_ `:` _case-list_ _case-expr_ ... `::` _default-expr_ -> _any_
 | [blue]`? : ::` | _Multi-Infix_ | _Index-Selector_ | _int-expr_ `?` _case-expr_ `:` _case-expr_ ... `::` _default-expr_ -> _any_
-.1+|*FRACT*| [blue]`\|` | _Infix_ | _Fraction_ | _integer_ `\|` _integer_ -> _fraction_
+.1+|*FRACT*| [blue]`:` | _Infix_ | _Fraction_ | _integer_ `:` _integer_ -> _fraction_
 .5+|*PROD*| [blue]`*` | _Infix_ | _Product_ | _number_ `*` _number_ -> _number_
 | [blue]`*` | _Infix_ | _String-repeat_ | _string_ `*` _integer_ -> _string_
 | [blue]`/` | _Infix_ | _Division_ | _number_ `/` _number_ -> _number_
@@ -765,6 +765,9 @@ The table below shows all supported operators by decreasing priorities.
 | [blue]`+` | _Infix_ |  _Dict-join_ | _dict_ `+` _dict_ -> _dict_
 | [blue]`-` | _Infix_ | _Subtraction_ | _number_ `-` _number_ -> _number_
 | [blue]`-` | _Infix_ | _List-difference_ | _list_ `-` _list_ -> _list_
+.1+|*BINARY NOT*| [blue]`~` | _Prefix_ | _Binary Not_ | `~` _number_ -> _number_
+.1+|*BINARY AND*| [blue]`&` | _Infix_ | _Binary And_ | _number_ `&` _number_ -> _number_
+.1+|*BINARY OR*| [blue]`\|` | _Infix_ | _Binary Or_ | _number_ `\|` _number_ -> _number_
 .8+|*RELATION*| [blue]`<` | _Infix_ | _Less_ | _comparable_ `<` _comparable_ -> _boolean_
 | [blue]`\<=` | _Infix_ |  _less-equal_ | _comparable_ `\<=` _comparable_ -> _boolean_
 | [blue]`>` | _Infix_ |  _Greater_ | _comparable_ `>` _comparable_ -> _boolean_
@@ -773,11 +776,13 @@ The table below shows all supported operators by decreasing priorities.
 | [blue]`!=` | _Infix_ |  _Not-equal_ | _comparable_ `!=` _comparable_ -> _boolean_
 | [blue]`in` | _Infix_ |  _Member-of-list_ | _any_ `in` _list_ -> _boolean_
 | [blue]`in` | _Infix_ |  _Key-of-dict_ | _any_ `in` _dict_ -> _boolean_
-.1+|*NOT*| [blue]`not` | _Prefix_ | _Not_ | `not` _boolean_ -> _boolean_
+.1+|*LOGIC NOT*| [blue]`not` | _Prefix_ | _Not_ | `not` _boolean_ -> _boolean_
-.2+|*AND*| [blue]`and` | _Infix_ | _And_ | _boolean_ `and` _boolean_ -> _boolean_
+.2+|*LOGIC 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_
+.2+|*LOGIC OR*| [blue]`or` | _Infix_ | _Or_ | _boolean_ `or` _boolean_ -> _boolean_
 | [blue]`\|\|` | _Infix_ | _Or_ | _boolean_ `\|\|` _boolean_ -> _boolean_
+.2+|*INSERT*| [blue]`+>` | _Infix_ | _Prepend_ | _any_ `+>` _list_ -> _list_
+| [blue]`<+` | _Infix_ | _Append_ | _list_ `<+` _any_ -> _list_
 .3+|*ASSIGN*| [blue]`=` | _Infix_ | _Assignment_ | _identifier_ `=` _any_ -> _any_
 | [blue]`>>` | _Infix_ | _Front-insert_ | _any_ `>>` _list_ -> _list_
 | [blue]`<<` | _Infix_ | _Back-insert_ | _list_ `<<` _any_ -> _list_

doc/Expr.html

@@ -474,6 +474,16 @@ pre.rouge .gh {
   color: #b8bb26;
   font-weight: bold;
 }
+pre.rouge .ge {
+  font-style: italic;
+}
+pre.rouge .ges {
+  font-weight: bold;
+  font-style: italic;
+}
+pre.rouge .gs {
+  font-weight: bold;
+}
 pre.rouge .k, pre.rouge .kn, pre.rouge .kp, pre.rouge .kr, pre.rouge .kv {
   color: #fb4934;
 }
@@ -745,16 +755,16 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
 9.5
 <span class="o">&gt;&gt;&gt;</span> 0xFD + 0b1 + 0o1 <i class="conum" data-value="1"></i><b>(1)</b>
 255
-<span class="o">&gt;&gt;&gt;</span> 1|2 + 2|3 <i class="conum" data-value="2"></i><b>(2)</b>
+<span class="o">&gt;&gt;&gt;</span> 1:2 + 2:3 <i class="conum" data-value="2"></i><b>(2)</b>
-7|6
+7:6
 <span class="o">&gt;&gt;&gt;</span> ml <i class="conum" data-value="3"></i><b>(3)</b>
-<span class="o">&gt;&gt;&gt;</span> 1|2 + 2|3
+<span class="o">&gt;&gt;&gt;</span> 1:2 + 2:3
 7
 -
 6
-<span class="o">&gt;&gt;&gt;</span> 4+2 but 5|2+0.5 <i class="conum" data-value="4"></i><b>(4)</b>
+<span class="o">&gt;&gt;&gt;</span> 4+2 but 5:2+0.5 <i class="conum" data-value="4"></i><b>(4)</b>
 3
-<span class="o">&gt;&gt;&gt;</span> 4+2<span class="p">;</span> 5|2+0.5 <i class="conum" data-value="5"></i><b>(5)</b>
+<span class="o">&gt;&gt;&gt;</span> 4+2<span class="p">;</span> 5:2+0.5 <i class="conum" data-value="5"></i><b>(5)</b>
 3
 <span class="o">&gt;&gt;&gt;</span></code></pre>
 </div>
@@ -767,7 +777,7 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
 </tr>
 <tr>
 <td><i class="conum" data-value="2"></i><b>2</b></td>
-<td>Fractions: <em>numerator</em> | <em>denominator</em>.</td>
+<td>Fractions: <em>numerator</em> : <em>denominator</em>.</td>
 </tr>
 <tr>
 <td><i class="conum" data-value="3"></i><b>3</b></td>
@@ -981,13 +991,13 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
 <div class="sect3">
 <h4 id="_fractions"><a class="anchor" href="#_fractions"></a><a class="link" href="#_fractions">2.1.3. Fractions</a></h4>
 <div class="paragraph">
-<p><em>Expr</em> also supports fractions. Fraction literals are made with two integers separated by a vertical bar <code>|</code>.</p>
+<p><em>Expr</em> also supports fractions. Fraction literals are made with two integers separated by a colon character <code>:</code>.</p>
 </div>
 <div class="exampleblock">
 <div class="title">Example 3. Fraction literal syntax</div>
 <div class="content">
 <div class="paragraph">
-<p><strong><em>fraction</em></strong> = [<em>sign</em>] (<em>num-den-spec</em> | <em>float-spec</em>)<br>
+<p><strong><em>fraction</em></strong> = [<em>sign</em>] (<em>num-den-spec</em> "<strong>:</strong>" <em>float-spec</em>)<br>
 <em>sign</em> = "<strong>+</strong>" | "<strong>-</strong>"<br>
 <em>num-den-spec</em> = <em>digit-seq</em> "<strong>|</strong>" <em>digit-seq</em><br>
 <em>float-spec</em> = <em>dec-seq</em> "<strong>.</strong>" [<em>dec-seq</em>] "<strong>(</strong>" <em>dec-seq</em> "<strong>)</strong>"<br>
@@ -998,55 +1008,55 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
 </div>
 <div class="paragraph">
 <div class="title">Examples</div>
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1 | 2</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1 : 2</code><br>
-<code class="green">1|2</code></p>
+<code class="green">1:2</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">4|6</code>  <em class="gray">// Fractions are always reduced to their lowest terms</em><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">4:6</code>  <em class="gray">// Fractions are always reduced to their lowest terms</em><br>
-<code class="green">2|3</code></p>
+<code class="green">2:3</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1|2 + 2|3</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1:2 + 2:3</code><br>
-<code class="green">7|6</code></p>
+<code class="green">7:6</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1|2 * 2|3</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1:2 * 2:3</code><br>
-<code class="green">1|3</code></p>
+<code class="green">1:3</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1|2 / 1|3</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1:2 / 1:3</code><br>
-<code class="green">3|2</code></p>
+<code class="green">3:2</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1|2 ./ 1|3</code> <em class="gray">// Force decimal division</em><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1:2 ./ 1:3</code> <em class="gray">// Force decimal division</em><br>
 <code class="green">1.5</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">-1|2</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">-1:2</code><br>
-<code class="green">-1|2</code></p>
+<code class="green">-1:2</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1|-2</code> <em class="gray">// Invalid sign specification</em><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1:-2</code> <em class="gray">// Invalid sign specification</em><br>
-<em class="red">Eval Error: [1:3] infix operator "|" requires two non-nil operands, got 1</em></p>
+<em class="red">Eval Error: [1:3] infix operator ":" requires two non-nil operands, got 1</em></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1|(-2)</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1:(-2)</code><br>
-<code class="green">-1|2</code></p>
+<code class="green">-1:2</code></p>
 </div>
 <div class="paragraph">
 <p>Fractions can be used together with integers and floats in expressions.</p>
 </div>
 <div class="paragraph">
 <div class="title">Examples</div>
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1|2 + 5</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1:2 + 5</code><br>
-<code class="green">11|2</code></p>
+<code class="green">11:2</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">4 - 1|2</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">4 - 1:2</code><br>
-<code class="green">7|2</code></p>
+<code class="green">7:2</code></p>
 </div>
 <div class="paragraph">
-<p><code>&gt;&gt;&gt;</code> <code class="blue">1.0 + 1|2</code><br>
+<p><code>&gt;&gt;&gt;</code> <code class="blue">1.0 + 1:2</code><br>
 <code class="green">1.5</code></p>
 </div>
 </div>
@@ -1370,16 +1380,16 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
 <td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">[1,2,3] - [2]</code> &#8594; <em>[1,3]</em></p></td>
 </tr>
 <tr>
-<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">&gt;&gt;</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">+&gt;</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Front insertion</em></p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">Insert an item in front</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">0 &gt;&gt; [1,2]</code> &#8594; <em>[0,1,2]</em></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">0 +&gt; [1,2]</code> &#8594; <em>[0,1,2]</em></p></td>
 </tr>
 <tr>
-<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">&lt;&lt;</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">&lt;+</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Back insertion</em></p></td>
 <td class="tableblock halign-left valign-top"><p class="tableblock">Insert an item at end</p></td>
-<td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">[1,2] &lt;&lt; 3</code> &#8594; <em>[1,2,3]</em></p></td>
+<td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">[1,2] &lt;+ 3</code> &#8594; <em>[1,2,3]</em></p></td>
 </tr>
 <tr>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">[]</code></p></td>
@@ -1890,11 +1900,11 @@ These operators have a high priority, in particular higher than the operator <co
 <table class="tableblock frame-all grid-all stretch">
 <caption class="title">Table 8. Operators priorities</caption>
 <colgroup>
-<col style="width: 11.7647%;">
+<col style="width: 16.6666%;">
-<col style="width: 11.7647%;">
+<col style="width: 11.1111%;">
-<col style="width: 11.7647%;">
+<col style="width: 11.1111%;">
-<col style="width: 29.4117%;">
+<col style="width: 27.7777%;">
-<col style="width: 35.2942%;">
+<col style="width: 33.3335%;">
 </colgroup>
 <thead>
 <tr>
@@ -1992,10 +2002,10 @@ These operators have a high priority, in particular higher than the operator <co
 </tr>
 <tr>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><strong>FRACT</strong></p></td>
-<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">|</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">:</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Fraction</em></p></td>
-<td class="tableblock halign-center valign-top"><p class="tableblock"><em>integer</em> <code>|</code> <em>integer</em> &#8594; <em>fraction</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>integer</em> <code>:</code> <em>integer</em> &#8594; <em>fraction</em></p></td>
 </tr>
 <tr>
 <td class="tableblock halign-center valign-top" rowspan="5"><p class="tableblock"><strong>PROD</strong></p></td>
@@ -2066,6 +2076,27 @@ These operators have a high priority, in particular higher than the operator <co
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>list</em> <code>-</code> <em>list</em> &#8594; <em>list</em></p></td>
 </tr>
 <tr>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><strong>BINARY NOT</strong></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">~</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Prefix</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Binary Not</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code>~</code> <em>number</em> &#8594; <em>number</em></p></td>
+</tr>
+<tr>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><strong>BINARY AND</strong></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">&amp;</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Binary And</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>number</em> <code>&amp;</code> <em>number</em> &#8594; <em>number</em></p></td>
+</tr>
+<tr>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><strong>BINARY OR</strong></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">|</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Binary Or</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>number</em> <code>|</code> <em>number</em> &#8594; <em>number</em></p></td>
+</tr>
+<tr>
 <td class="tableblock halign-center valign-top" rowspan="8"><p class="tableblock"><strong>RELATION</strong></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">&lt;</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
@@ -2115,14 +2146,14 @@ These operators have a high priority, in particular higher than the operator <co
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>any</em> <code>in</code> <em>dict</em> &#8594; <em>boolean</em></p></td>
 </tr>
 <tr>
-<td class="tableblock halign-center valign-top"><p class="tableblock"><strong>NOT</strong></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><strong>LOGIC NOT</strong></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">not</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Prefix</em></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Not</em></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><code>not</code> <em>boolean</em> &#8594; <em>boolean</em></p></td>
 </tr>
 <tr>
-<td class="tableblock halign-center valign-top" rowspan="2"><p class="tableblock"><strong>AND</strong></p></td>
+<td class="tableblock halign-center valign-top" rowspan="2"><p class="tableblock"><strong>LOGIC AND</strong></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">and</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>And</em></p></td>
@@ -2135,7 +2166,7 @@ These operators have a high priority, in particular higher than the operator <co
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>boolean</em> <code>&amp;&amp;</code> <em>boolean</em> &#8594; <em>boolean</em></p></td>
 </tr>
 <tr>
-<td class="tableblock halign-center valign-top" rowspan="2"><p class="tableblock"><strong>OR</strong></p></td>
+<td class="tableblock halign-center valign-top" rowspan="2"><p class="tableblock"><strong>LOGIC OR</strong></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">or</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Or</em></p></td>
@@ -2148,6 +2179,19 @@ These operators have a high priority, in particular higher than the operator <co
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>boolean</em> <code>||</code> <em>boolean</em> &#8594; <em>boolean</em></p></td>
 </tr>
 <tr>
+<td class="tableblock halign-center valign-top" rowspan="2"><p class="tableblock"><strong>INSERT</strong></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">+&gt;</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Prepend</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>any</em> <code>+&gt;</code> <em>list</em> &#8594; <em>list</em></p></td>
+</tr>
+<tr>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">&lt;+</code></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Append</em></p></td>
+<td class="tableblock halign-center valign-top"><p class="tableblock"><em>list</em> <code>&lt;+</code> <em>any</em> &#8594; <em>list</em></p></td>
+</tr>
+<tr>
 <td class="tableblock halign-center valign-top" rowspan="3"><p class="tableblock"><strong>ASSIGN</strong></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">=</code></p></td>
 <td class="tableblock halign-center valign-top"><p class="tableblock"><em>Infix</em></p></td>
@@ -2432,7 +2476,7 @@ g(@p):any{}`
 </div>
 <div id="footer">
 <div id="footer-text">
-Last updated 2024-09-30 07:29:03 +0200
+Last updated 2024-12-28 09:13:00 +0100
 </div>
 </div>
 </body>

fraction-type.go

@@ -126,34 +126,36 @@ func (f *FractionType) ToString(opt FmtOpt) string {
 	if opt&MultiLine == 0 {
 		sb.WriteString(fmt.Sprintf("%d:%d", f.num, f.den))
 	} else {
-		var s, num string
+		var sign, num string
 		if f.num < 0 && opt&TTY == 0 {
 			num = strconv.FormatInt(-f.num, 10)
-			s = "-"
+			sign = "-"
 		} else {
 			num = strconv.FormatInt(f.num, 10)
 		}
 		den := strconv.FormatInt(f.den, 10)
 		size := max(len(num), len(den))
 		if opt&TTY != 0 {
-			sb.WriteString(fmt.Sprintf("\x1b[4m%[1]*s\x1b[0m\n", -size, fmt.Sprintf("%[1]*s", (size+len(num))/2, s+num)))
+			sNum := fmt.Sprintf("\x1b[4m%[1]*s\x1b[0m\n", -size, fmt.Sprintf("%[1]*s", (size+len(num))/2, sign+num))
+			sb.WriteString(sNum)
 		} else {
-			if len(s) > 0 {
+			if len(sign) > 0 {
 				sb.WriteString("  ")
 			}
 			sb.WriteString(fmt.Sprintf("%[1]*s", -size, fmt.Sprintf("%[1]*s", (size+len(num))/2, num)))
 			sb.WriteByte('\n')
-			if len(s) > 0 {
+			if len(sign) > 0 {
-				sb.WriteString(s)
+				sb.WriteString(sign)
 				sb.WriteByte(' ')
 			}
 			sb.WriteString(strings.Repeat("-", size))
 			sb.WriteByte('\n')
-			if len(s) > 0 {
+			if len(sign) > 0 {
 				sb.WriteString("  ")
 			}
 		}
-		sb.WriteString(fmt.Sprintf("%[1]*s", -size, fmt.Sprintf("%[1]*s", (size+len(den))/2, den)))
+		sDen := fmt.Sprintf("%[1]*s", size, fmt.Sprintf("%[1]*s", (size+len(den))/2, den))
+		sb.WriteString(sDen)
 	}
 
 	return sb.String()

iterator.go

@@ -5,7 +5,7 @@
 package expr
 
 import (
-	"errors"
+	// "errors"
 	"fmt"
 )
 
@@ -43,6 +43,6 @@ func errNoOperation(name string) error {
 	return fmt.Errorf("no %s() function defined in the data-source", name)
 }
 
-func errInvalidDataSource() error {
+// func errInvalidDataSource() error {
-	return errors.New("invalid data-source")
+// 	return errors.New("invalid data-source")
-}
+// }

operator-binary.go

@@ -11,7 +11,7 @@ func newBinNotTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 1),
 		position: posPrefix,
-		priority: priNot,
+		priority: priBinNot,
 		evalFunc: evalBinaryNot,
 	}
 }
@@ -39,7 +39,7 @@ func newBinAndTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priAnd,
+		priority: priBinAnd,
 		evalFunc: evalBinaryAnd,
 	}
 }
@@ -71,7 +71,7 @@ func newBinOrTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priOr,
+		priority: priBinOr,
 		evalFunc: evalBinaryOr,
 	}
 }

operator-context.go

@@ -20,7 +20,7 @@ func evalContextValue(ctx ExprContext, opTerm *term) (v any, err error) {
 	var childValue any
 
 	var sourceCtx ExprContext
-	if opTerm.children == nil || len(opTerm.children) == 0 {
+	if len(opTerm.children) == 0 {
 		sourceCtx = ctx
 	} else if opTerm.children[0].symbol() == SymVariable && opTerm.children[0].source() == "global" {
 		sourceCtx = globalCtx

operator-insert.go

@@ -4,15 +4,15 @@
 // operator-insert.go
 package expr
 
-//-------- insert term
+//-------- prepend term
 
-func newInsertTerm(tk *Token) (inst *term) {
+func newPrependTerm(tk *Token) (inst *term) {
 	return &term{
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priAssign,
+		priority: priInsert,
-		evalFunc: evalInsert,
+		evalFunc: evalPrepend,
 	}
 }
 
@@ -21,12 +21,12 @@ func newAppendTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priAssign,
+		priority: priInsert,
 		evalFunc: evalAppend,
 	}
 }
 
-func evalInsert(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalPrepend(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any
 
 	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
@@ -40,10 +40,6 @@ func evalInsert(ctx ExprContext, opTerm *term) (v any, err error) {
 		if opTerm.children[1].symbol() == SymVariable {
 			ctx.UnsafeSetVar(opTerm.children[1].source(), v)
 		}
-	} else if IsInteger(leftValue) && IsInteger(rightValue) {
-		leftInt := leftValue.(int64)
-		rightInt := rightValue.(int64)
-		v = leftInt >> rightInt
 	} else {
 		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -64,10 +60,6 @@ func evalAppend(ctx ExprContext, opTerm *term) (v any, err error) {
 		if opTerm.children[0].symbol() == SymVariable {
 			ctx.UnsafeSetVar(opTerm.children[0].source(), v)
 		}
-	} else if IsInteger(leftValue) && IsInteger(rightValue) {
-		leftInt := leftValue.(int64)
-		rightInt := rightValue.(int64)
-		v = leftInt << rightInt
 	} else {
 		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
 	}
@@ -94,6 +86,6 @@ func evalAppend(ctx ExprContext, opTerm *term) (v any, err error) {
 
 // init
 func init() {
-	registerTermConstructor(SymInsert, newInsertTerm)
+	registerTermConstructor(SymPlusGreater, newPrependTerm)
-	registerTermConstructor(SymAppend, newAppendTerm)
+	registerTermConstructor(SymLessPlus, newAppendTerm)
 }

operator-shift.go

@@ -0,0 +1,85 @@
+// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
+// All rights reserved.
+
+// operator-shift.go
+package expr
+
+//-------- shift term
+
+func newRightShiftTerm(tk *Token) (inst *term) {
+	return &term{
+		tk:       *tk,
+		children: make([]*term, 0, 2),
+		position: posInfix,
+		priority: priBinShift,
+		evalFunc: evalRightShift,
+	}
+}
+
+func evalRightShift(ctx ExprContext, opTerm *term) (v any, err error) {
+	var leftValue, rightValue any
+
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+		return
+	}
+
+	if IsInteger(leftValue) && IsInteger(rightValue) {
+		leftInt := leftValue.(int64)
+		rightInt := rightValue.(int64)
+		v = leftInt >> rightInt
+	} else {
+		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
+	}
+	return
+}
+
+func newLeftShiftTerm(tk *Token) (inst *term) {
+	return &term{
+		tk:       *tk,
+		children: make([]*term, 0, 2),
+		position: posInfix,
+		priority: priBinShift,
+		evalFunc: evalLeftShift,
+	}
+}
+
+func evalLeftShift(ctx ExprContext, opTerm *term) (v any, err error) {
+	var leftValue, rightValue any
+
+	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
+		return
+	}
+
+	if IsInteger(leftValue) && IsInteger(rightValue) {
+		leftInt := leftValue.(int64)
+		rightInt := rightValue.(int64)
+		v = leftInt << rightInt
+	} else {
+		err = opTerm.errIncompatibleTypes(leftValue, rightValue)
+	}
+	return
+}
+
+// func evalAssignAppend(ctx ExprContext, self *term) (v any, err error) {
+// 	var leftValue, rightValue any
+
+// 	if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
+// 		return
+// 	}
+
+// 	if IsList(leftValue) {
+// 		list, _ := leftValue.(*ListType)
+// 		newList := append(*list, rightValue)
+// 		v = &newList
+// 		if
+// 	} else {
+// 		err = self.errIncompatibleTypes(leftValue, rightValue)
+// 	}
+// 	return
+// }
+
+// init
+func init() {
+	registerTermConstructor(SymDoubleGreater, newRightShiftTerm)
+	registerTermConstructor(SymDoubleLess, newLeftShiftTerm)
+}

parser.go

@@ -441,6 +441,9 @@ func (parser *parser) parseGeneral(scanner *scanner, ctx parserContext, termSymb
 				tk.Sym = SymChangeSign
 			} else if tk.Sym == SymPlus {
 				tk.Sym = SymUnchangeSign
+			} else if tk.IsSymbol(SymExclamation) {
+				err = tk.Errorf("postfix opertor %q requires an operand on its left", tk)
+				break
 			}
 			firstToken = false
 		}

scanner.go

@@ -124,6 +124,8 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 				tk = scanner.moveOn(SymDoublePlus, ch, next)
 			} else if next == '=' {
 				tk = scanner.moveOn(SymPlusEqual, ch, next)
+			} else if next == '>' {
+				tk = scanner.moveOn(SymPlusGreater, ch, next)
 			} else {
 				tk = scanner.makeToken(SymPlus, ch)
 			}
@@ -265,9 +267,11 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := scanner.peek(); next == '=' {
 				tk = scanner.moveOn(SymLessOrEqual, ch, next)
 			} else if next == '<' {
-				tk = scanner.moveOn(SymAppend, ch, next)
+				tk = scanner.moveOn(SymDoubleLess, ch, next)
 			} else if next == '>' {
 				tk = scanner.moveOn(SymLessGreater, ch, next)
+			} else if next == '+' {
+				tk = scanner.moveOn(SymLessPlus, ch, next)
 			} else {
 				tk = scanner.makeToken(SymLess, ch)
 			}
@@ -275,7 +279,7 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := scanner.peek(); next == '=' {
 				tk = scanner.moveOn(SymGreaterOrEqual, ch, next)
 			} else if next == '>' {
-				tk = scanner.moveOn(SymInsert, ch, next)
+				tk = scanner.moveOn(SymDoubleGreater, ch, next)
 			} else {
 				tk = scanner.makeToken(SymGreater, ch)
 			}
@@ -460,7 +464,7 @@ func (scanner *scanner) parseNumber(firstCh byte) (tk *Token) {
 		tk = scanner.makeErrorToken(err)
 	} else {
 		var value any
-		err = scanner.sync(err) // TODO: Check this function
+		_ = scanner.sync(err) // TODO: Check this function
 		txt := sb.String()
 		if sym == SymFloat {
 			value, err = strconv.ParseFloat(txt, 64)

symbol-map.go

@@ -84,8 +84,8 @@ func init() {
 		SymQuestionExclam:  {"?!", symClassOperator},     //  49: '?!'
 		SymDoubleAt:        {"@@", symClassOperator},     //  50: '@@'
 		SymDoubleColon:     {"::", symClassOperator},     //  51: '::'
-		SymInsert:          {">>", symClassOperator},     //  52: '>>'
+		SymDoubleGreater:   {">>", symClassOperator},     //  52: '>>'
-		SymAppend:          {"<<", symClassOperator},     //  53: '<<'
+		SymDoubleLess:      {"<<", symClassOperator},     //  53: '<<'
 		SymCaret:           {"^", symClassOperator},      //  54: '^'
 		SymDollarRound:     {"$(", symClassOperator},     //  55: '$('
 		SymOpenClosedRound: {"()", symClassPostOp},       //  56: '()'
@@ -95,6 +95,8 @@ func init() {
 		SymStarEqual:       {"*=", symClassOperator},     //  60: '*='
 		SymSlashEqual:      {"/=", symClassOperator},     //  61: '/='
 		SymPercEqual:       {"%=", symClassOperator},     //  62: '%='
+		SymPlusGreater:     {"+>", symClassOperator},     //  63: '+>'
+		SymLessPlus:        {"<+", symClassOperator},     //  64: '<+'
 		// SymChangeSign
 		// SymUnchangeSign
 		// SymIdentifier

symbol.go

@@ -60,8 +60,8 @@ const (
 	SymQuestionExclam                    //  49: '?!'
 	SymDoubleAt                          //  50: '@@'
 	SymDoubleColon                       //  51: '::'
-	SymInsert                            //  52: '>>'
+	SymDoubleGreater                     //  52: '>>'
-	SymAppend                            //  53: '<<'
+	SymDoubleLess                        //  53: '<<'
 	SymCaret                             //  54: '^'
 	SymDollarRound                       //  55: '$('
 	SymOpenClosedRound                   //  56: '()'
@@ -71,6 +71,8 @@ const (
 	SymStarEqual                         //  60: '*='
 	SymSlashEqual                        //  61: '/='
 	SymPercEqual                         //  62: '%='
+	SymPlusGreater                       //  63: '+>'
+	SymLessPlus                          //  64: '<+'
 	SymChangeSign
 	SymUnchangeSign
 	SymIdentifier

t_builtin-base_test.go

@@ -56,11 +56,12 @@ func TestFuncBase(t *testing.T) {
 		/*  42 */ {`dec(false)`, float64(0), nil},
 		/*  43 */ {`dec(1:2)`, float64(0.5), nil},
 		/*  44 */ {`dec([1])`, nil, `dec(): can't convert list to float`},
+		/*  45 */ {`eval("a=3"); a`, int64(3), nil},
 		// /*  45 */ {`string([1])`, nil, `string(): can't convert list to string`},
 	}
 
 	t.Setenv("EXPR_PATH", ".")
 
-	// runTestSuiteSpec(t, section, inputs, 30)
+	// runTestSuiteSpec(t, section, inputs, 45)
 	runTestSuite(t, section, inputs)
 }

t_builtin-string_test.go

@@ -15,7 +15,7 @@ func TestFuncString(t *testing.T) {
 		/*   1 */ {`builtin "string"; strJoin("-", "one", "two", "three")`, "one-two-three", nil},
 		/*   2 */ {`builtin "string"; strJoin("-", ["one", "two", "three"])`, "one-two-three", nil},
 		/*   3 */ {`builtin "string"; ls= ["one", "two", "three"]; strJoin("-", ls)`, "one-two-three", nil},
-		/*   4 */ {`builtin "string"; ls= ["one", "two", "three"]; strJoin(1, ls)`, nil, `strJoin(): the "separator" parameter must be a string, got a integer (1)`},
+		/*   4 */ {`builtin "string"; ls= ["one", "two", "three"]; strJoin(1, ls)`, nil, `strJoin(): the "separator" parameter must be a string, got an integer (1)`},
 		/*   5 */ {`builtin "string"; ls= ["one", 2, "three"]; strJoin("-", ls)`, nil, `strJoin(): expected string, got integer (2)`},
 		/*   6 */ {`builtin "string"; "<"+strTrim("  bye bye  ")+">"`, "<bye bye>", nil},
 		/*   7 */ {`builtin "string"; strSub("0123456789", 1,2)`, "12", nil},

t_fractions_test.go

@@ -59,10 +59,9 @@ func TestFractionToStringMultiline(t *testing.T) {
 	}
 }
 
-// TODO Check this test: the output string ends with a space
+func TestToStringMultilineTty(t *testing.T) {
-func _TestToStringMultilineTty(t *testing.T) {
 	source := newFraction(-1, 2)
-	want := "\x1b[4m-1\x1b[0m\n2"
+	want := "\x1b[4m-1\x1b[0m\n 2"
 	got := source.ToString(MultiLine | TTY)
 	if got != want {
 		t.Errorf(`(1,2) -> result = %#v [%T], want = %#v [%T]`, got, got, want, want)

t_list_test.go

@@ -23,8 +23,8 @@ func TestListParser(t *testing.T) {
 		/*   9 */ {`mul([1,4,3.0,2])`, float64(24.0), nil},
 		/*  10 */ {`add([1,"hello"])`, nil, `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`, newListA(int64(1), int64(2), int64(3), int64(4)), nil},
+		/*  12 */ {`[1,2,3] <+ 2+2`, newListA(int64(1), int64(2), int64(3), int64(4)), nil},
-		/*  13 */ {`2-1 >> [2,3]`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  13 */ {`2-1 +> [2,3]`, newListA(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},
@@ -33,8 +33,8 @@ func TestListParser(t *testing.T) {
 		/*  19 */ {`["a", "b", "c"]`, newList([]any{"a", "b", "c"}), nil},
 		/*  20 */ {`#["a", "b", "c"]`, int64(3), nil},
 		/*  21 */ {`"b" in ["a", "b", "c"]`, true, nil},
-		/*  22 */ {`a=[1,2]; (a)<<3`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  22 */ {`a=[1,2]; (a)<+3`, newListA(int64(1), int64(2), int64(3)), nil},
-		/*  23 */ {`a=[1,2]; (a)<<3; a`, newListA(int64(1), int64(2)), nil},
+		/*  23 */ {`a=[1,2]; (a)<+3; a`, newListA(int64(1), int64(2)), nil},
 		/*  24 */ {`["a","b","c","d"][1]`, "b", nil},
 		/*  25 */ {`["a","b","c","d"][1,1]`, nil, `[1:19] one index only is allowed`},
 		/*  26 */ {`[0,1,2,3,4][:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
@@ -42,16 +42,16 @@ func TestListParser(t *testing.T) {
 		/*  28 */ {`2 << 3;`, int64(16), nil},
 		/*  29 */ {`but >> ["a", "b", "c"]`, nil, `[1:6] infix operator ">>" requires two non-nil operands, got 0`},
 		/*  30 */ {`2 >> 3;`, int64(0), nil},
-		/*  31 */ {`a=[1,2]; a<<3`, newListA(int64(1), int64(2), int64(3)), nil},
+		/*  31 */ {`a=[1,2]; a<+3`, newListA(int64(1), int64(2), int64(3)), nil},
-		/*  33 */ {`a=[1,2]; 5>>a`, newListA(int64(5), int64(1), int64(2)), nil},
+		/*  32 */ {`a=[1,2]; 5+>a`, newListA(int64(5), int64(1), int64(2)), nil},
-		/*  34 */ {`L=[1,2]; L[0]=9; L`, newListA(int64(9), int64(2)), nil},
+		/*  33 */ {`L=[1,2]; L[0]=9; L`, newListA(int64(9), int64(2)), nil},
-		/*  35 */ {`L=[1,2]; L[5]=9; L`, nil, `index 5 out of bounds (0, 1)`},
+		/*  34 */ {`L=[1,2]; L[5]=9; L`, nil, `index 5 out of bounds (0, 1)`},
-		/*  36 */ {`L=[1,2]; L[]=9; L`, nil, `[1:12] index/key specification expected, got [] [list]`},
+		/*  35 */ {`L=[1,2]; L[]=9; L`, nil, `[1:12] index/key specification expected, got [] [list]`},
-		/*  37 */ {`L=[1,2]; L[nil]=9;`, nil, `[1:12] index/key is nil`},
+		/*  36 */ {`L=[1,2]; L[nil]=9;`, nil, `[1:12] index/key is nil`},
-		/*  38 */ {`[0,1,2,3,4][2:3]`, newListA(int64(2)), nil},
+		/*  37 */ {`[0,1,2,3,4][2:3]`, newListA(int64(2)), nil},
-		/*  39 */ {`[0,1,2,3,4][3:-1]`, newListA(int64(3)), nil},
+		/*  38 */ {`[0,1,2,3,4][3:-1]`, newListA(int64(3)), nil},
-		/*  40 */ {`[0,1,2,3,4][-3:-1]`, newListA(int64(2), int64(3)), nil},
+		/*  30 */ {`[0,1,2,3,4][-3:-1]`, newListA(int64(2), int64(3)), nil},
-		/*  41 */ {`[0,1,2,3,4][0:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
+		/*  40 */ {`[0,1,2,3,4][0:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
 	}
 
 	// t.Setenv("EXPR_PATH", ".")

t_plugin_test.go

@@ -8,18 +8,18 @@ import (
 	"testing"
 )
 
-func _TestImportPlugin(t *testing.T) {
+// func TestImportPlugin(t *testing.T) {
-	t.Setenv("PLUGINS", "${HOME}/go/src/git.portale-stac.it/go")
+// 	t.Setenv("PLUGINS", "${HOME}/go/src/git.portale-stac.it/go")
-	t.Setenv("EXPR_PLUGIN_PATH","${PLUGINS}/expr-json-plugin:${PLUGINS}/expr-csv-plugin")
+// 	t.Setenv("EXPR_PLUGIN_PATH","${PLUGINS}/expr-json-plugin:${PLUGINS}/expr-csv-plugin")
 
-	gotCount, gotErr := importPluginFromSearchPath("json")
+// 	gotCount, gotErr := importPluginFromSearchPath("json")
-	if gotCount != 1 {
+// 	if gotCount != 1 {
-		t.Errorf("Import count: got=%d, want=1", gotCount)
+// 		t.Errorf("Import count: got=%d, want=1", gotCount)
-	}
+// 	}
-	if gotErr != nil {
+// 	if gotErr != nil {
-		t.Errorf("importPlugin() failed: %v", gotErr)
+// 		t.Errorf("importPlugin() failed: %v", gotErr)
-	}
+// 	}
-}
+// }
 
 func TestPluginExists(t *testing.T) {
 	name := "json"

term.go

@@ -15,14 +15,19 @@ const (
 	priRange
 	priBut
 	priAssign
+	priInsert
 	priOr
 	priAnd
 	priNot
 	priRelational
+	priBinOr
+	priBinAnd
+	priBinNot
 	priSum
 	priProduct
 	priFraction
 	priSelector
+	priBinShift
 	priSign
 	priFact
 	priIterValue