Doc: fractions and dictionaries

doc/Expr.adoc

@@ -22,7 +22,7 @@ Expressions calculator
 
 toc::[]
 
-#TODO: Work in progress (last update on 2024/05/07, 07:15 am)#
+#TODO: Work in progress (last update on 2024/05/09, 07:17 am)#
 
 == Expr
 _Expr_ is a GO package capable of analysing, interpreting and calculating expressions.
@@ -140,7 +140,44 @@ Numbers can be integers (GO int64) or float (GO float64). In mixed operations in
 
 |=== 
 
-=== String
+=== Fractions
+_Expr_ also suports fractions. Fraction literals are made with tow 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 theri 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.
@@ -232,6 +269,19 @@ _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] ]_
 |===
 
+== 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.