10 changed files with 69 additions and 175 deletions
--- a/doc/Expr.adoc
+++ b/doc/Expr.adoc
@ -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]`<+` | _Back insertion_ | Insert an item at end | [blue]`[1,2] <+ 3` -> _[1,2,3]_
+| [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]`[]` | _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="^3,^2,^2,^5,^6"]
+[cols="^2,^2,^2,^5,^6"]
 |===
 | Priority | Operators     | Position | Operation | Operands and results

@ -765,9 +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_
+.3+|*BINARY*| [blue]`&` | _Infix_ | _Binary And_ | _number_ `&` _number_ -> _number_
+| [blue]`\|` | _Infix_ | _Binary Or_ | _number_ `\|` _number_ -> _number_
+| [blue]`~` | _Prefix_ | _Binary Not_ | `~` _number_ -> _number_
 .8+|*RELATION*| [blue]`<` | _Infix_ | _Less_ | _comparable_ `<` _comparable_ -> _boolean_
 | [blue]`\<=` | _Infix_ |  _less-equal_ | _comparable_ `\<=` _comparable_ -> _boolean_
 | [blue]`>` | _Infix_ |  _Greater_ | _comparable_ `>` _comparable_ -> _boolean_
@ -776,13 +776,11 @@ 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+|*LOGIC NOT*| [blue]`not` | _Prefix_ | _Not_ | `not` _boolean_ -> _boolean_
-.2+|*LOGIC AND*| [blue]`and` | _Infix_ | _And_ | _boolean_ `and` _boolean_ -> _boolean_
+.1+|*NOT*| [blue]`not` | _Prefix_ | _Not_ | `not` _boolean_ -> _boolean_
+.2+|*AND*| [blue]`and` | _Infix_ | _And_ | _boolean_ `and` _boolean_ -> _boolean_
 | [blue]`&&` | _Infix_ | _And_ | _boolean_ `&&` _boolean_ -> _boolean_
-.2+|*LOGIC OR*| [blue]`or` | _Infix_ | _Or_ | _boolean_ `or` _boolean_ -> _boolean_
+.2+|*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_
--- a/doc/Expr.html
+++ b/doc/Expr.html
@ -1380,16 +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;</code></p></td>
+<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"><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; [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;&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;+</code></p></td>
+<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"><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;+ 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;&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>
@ -1900,11 +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: 16.6666%;">
-<col style="width: 11.1111%;">
-<col style="width: 11.1111%;">
-<col style="width: 27.7777%;">
-<col style="width: 33.3335%;">
+<col style="width: 11.7647%;">
+<col style="width: 11.7647%;">
+<col style="width: 11.7647%;">
+<col style="width: 29.4117%;">
+<col style="width: 35.2942%;">
 </colgroup>
 <thead>
 <tr>
@ -2076,27 +2076,25 @@ 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" rowspan="3"><p class="tableblock"><strong>BINARY</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"><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" 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>
@ -2146,14 +2144,14 @@ 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>LOGIC NOT</strong></p></td>
+<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"><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>LOGIC AND</strong></p></td>
+<td class="tableblock halign-center valign-top" rowspan="2"><p class="tableblock"><strong>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>
@ -2166,7 +2164,7 @@ 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>LOGIC OR</strong></p></td>
+<td class="tableblock halign-center valign-top" rowspan="2"><p class="tableblock"><strong>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>
@ -2179,19 +2177,6 @@ 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>
@ -2476,7 +2461,7 @@ g(@p):any{}`
 </div>
 <div id="footer">
 <div id="footer-text">
-Last updated 2024-12-28 09:13:00 +0100
+Last updated 2024-12-23 07:20:48 +0100
 </div>
 </div>
 </body>
--- a/operator-binary.go
+++ b/operator-binary.go
@ -11,7 +11,7 @@ func newBinNotTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 1),
 		position: posPrefix,
-		priority: priBinNot,
+		priority: priBinary,
 		evalFunc: evalBinaryNot,
 	}
 }
@ -39,7 +39,7 @@ func newBinAndTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priBinAnd,
+		priority: priBinary,
 		evalFunc: evalBinaryAnd,
 	}
 }
@ -71,7 +71,7 @@ func newBinOrTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priBinOr,
+		priority: priBinary,
 		evalFunc: evalBinaryOr,
 	}
 }
--- a/operator-insert.go
+++ b/operator-insert.go
@ -4,15 +4,15 @@
 // operator-insert.go
 package expr

-//-------- prepend term
+//-------- insert term

-func newPrependTerm(tk *Token) (inst *term) {
+func newInsertTerm(tk *Token) (inst *term) {
 	return &term{
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priInsert,
-		evalFunc: evalPrepend,
+		priority: priAssign,
+		evalFunc: evalInsert,
 	}
 }

@ -21,12 +21,12 @@ func newAppendTerm(tk *Token) (inst *term) {
 		tk:       *tk,
 		children: make([]*term, 0, 2),
 		position: posInfix,
-		priority: priInsert,
+		priority: priAssign,
 		evalFunc: evalAppend,
 	}
 }

-func evalPrepend(ctx ExprContext, opTerm *term) (v any, err error) {
+func evalInsert(ctx ExprContext, opTerm *term) (v any, err error) {
 	var leftValue, rightValue any

 	if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
@ -40,6 +40,10 @@ func evalPrepend(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)
 	}
@ -60,6 +64,10 @@ 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)
 	}
@ -86,6 +94,6 @@ func evalAppend(ctx ExprContext, opTerm *term) (v any, err error) {

 // init
 func init() {
-	registerTermConstructor(SymPlusGreater, newPrependTerm)
-	registerTermConstructor(SymLessPlus, newAppendTerm)
+	registerTermConstructor(SymInsert, newInsertTerm)
+	registerTermConstructor(SymAppend, newAppendTerm)
 }
--- a/operator-shift.go
+++ b/operator-shift.go
@ -1,85 +0,0 @@
-// 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)
-}
--- a/scanner.go
+++ b/scanner.go
@ -124,8 +124,6 @@ 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)
 			}
@ -267,11 +265,9 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := scanner.peek(); next == '=' {
 				tk = scanner.moveOn(SymLessOrEqual, ch, next)
 			} else if next == '<' {
-				tk = scanner.moveOn(SymDoubleLess, ch, next)
+				tk = scanner.moveOn(SymAppend, 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)
 			}
@ -279,7 +275,7 @@ func (scanner *scanner) fetchNextToken() (tk *Token) {
 			if next, _ := scanner.peek(); next == '=' {
 				tk = scanner.moveOn(SymGreaterOrEqual, ch, next)
 			} else if next == '>' {
-				tk = scanner.moveOn(SymDoubleGreater, ch, next)
+				tk = scanner.moveOn(SymInsert, ch, next)
 			} else {
 				tk = scanner.makeToken(SymGreater, ch)
 			}
--- a/symbol-map.go
+++ b/symbol-map.go
@ -84,8 +84,8 @@ func init() {
 		SymQuestionExclam:  {"?!", symClassOperator},     //  49: '?!'
 		SymDoubleAt:        {"@@", symClassOperator},     //  50: '@@'
 		SymDoubleColon:     {"::", symClassOperator},     //  51: '::'
-		SymDoubleGreater:   {">>", symClassOperator},     //  52: '>>'
-		SymDoubleLess:      {"<<", symClassOperator},     //  53: '<<'
+		SymInsert:          {">>", symClassOperator},     //  52: '>>'
+		SymAppend:          {"<<", symClassOperator},     //  53: '<<'
 		SymCaret:           {"^", symClassOperator},      //  54: '^'
 		SymDollarRound:     {"$(", symClassOperator},     //  55: '$('
 		SymOpenClosedRound: {"()", symClassPostOp},       //  56: '()'
@ -95,8 +95,6 @@ func init() {
 		SymStarEqual:       {"*=", symClassOperator},     //  60: '*='
 		SymSlashEqual:      {"/=", symClassOperator},     //  61: '/='
 		SymPercEqual:       {"%=", symClassOperator},     //  62: '%='
-		SymPlusGreater:     {"+>", symClassOperator},     //  63: '+>'
-		SymLessPlus:        {"<+", symClassOperator},     //  64: '<+'
 		// SymChangeSign
 		// SymUnchangeSign
 		// SymIdentifier
--- a/symbol.go
+++ b/symbol.go
@ -60,8 +60,8 @@ const (
 	SymQuestionExclam                    //  49: '?!'
 	SymDoubleAt                          //  50: '@@'
 	SymDoubleColon                       //  51: '::'
-	SymDoubleGreater                     //  52: '>>'
-	SymDoubleLess                        //  53: '<<'
+	SymInsert                            //  52: '>>'
+	SymAppend                            //  53: '<<'
 	SymCaret                             //  54: '^'
 	SymDollarRound                       //  55: '$('
 	SymOpenClosedRound                   //  56: '()'
@ -71,8 +71,6 @@ const (
 	SymStarEqual                         //  60: '*='
 	SymSlashEqual                        //  61: '/='
 	SymPercEqual                         //  62: '%='
-	SymPlusGreater                       //  63: '+>'
-	SymLessPlus                          //  64: '<+'
 	SymChangeSign
 	SymUnchangeSign
 	SymIdentifier
--- a/t_list_test.go
+++ b/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},
-		/*  13 */ {`2-1 +> [2,3]`, newListA(int64(1), int64(2), int64(3)), 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},
 		/*  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},
-		/*  23 */ {`a=[1,2]; (a)<+3; a`, newListA(int64(1), int64(2)), 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},
 		/*  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},
-		/*  32 */ {`a=[1,2]; 5+>a`, newListA(int64(5), int64(1), int64(2)), nil},
-		/*  33 */ {`L=[1,2]; L[0]=9; L`, newListA(int64(9), int64(2)), nil},
-		/*  34 */ {`L=[1,2]; L[5]=9; L`, nil, `index 5 out of bounds (0, 1)`},
-		/*  35 */ {`L=[1,2]; L[]=9; L`, nil, `[1:12] index/key specification expected, got [] [list]`},
-		/*  36 */ {`L=[1,2]; L[nil]=9;`, nil, `[1:12] index/key is nil`},
-		/*  37 */ {`[0,1,2,3,4][2:3]`, newListA(int64(2)), nil},
-		/*  38 */ {`[0,1,2,3,4][3:-1]`, newListA(int64(3)), nil},
-		/*  30 */ {`[0,1,2,3,4][-3:-1]`, newListA(int64(2), int64(3)), nil},
-		/*  40 */ {`[0,1,2,3,4][0:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), 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},
+		/*  34 */ {`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)`},
+		/*  36 */ {`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`},
+		/*  38 */ {`[0,1,2,3,4][2:3]`, newListA(int64(2)), nil},
+		/*  39 */ {`[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},
+		/*  41 */ {`[0,1,2,3,4][0:]`, newListA(int64(0), int64(1), int64(2), int64(3), int64(4)), nil},
 	}

 	// t.Setenv("EXPR_PATH", ".")
--- a/term.go
+++ b/term.go
@ -15,19 +15,15 @@ const (
 	priRange
 	priBut
 	priAssign
-	priInsert
 	priOr
 	priAnd
 	priNot
 	priRelational
-	priBinOr
-	priBinAnd
-	priBinNot
+	priBinary
 	priSum
 	priProduct
 	priFraction
 	priSelector
-	priBinShift
 	priSign
 	priFact
 	priIterValue