Doc: some typo and better examples

doc/Expr.adoc

@@ -203,19 +203,16 @@ The items of strings can be accessed using the dot `.` operator.
 ----
 
 .String examples
-[source,go]
-----
-`>>>` [blue]`s="abc"`  [gray]`// assign the string to variable s`
-[geen]`abc`
-`>>>` [blue]`s.1`      [gray]`// char at position 1 (starting from 0)
-[blue]`b`
-`>>>` [blue]`s.(-1)`   [gray]`// char at position -1, the rightmost one
-[blue]`c`
-`>>>` [blue]`#s`       [gray]`// number of chars
-[blue]3`
-`>>>` [blue]`#"abc"`   [gray]`// number of chars
-[blue]3`
-----
+`>>>` [blue]`s="abc"`  [gray]_assign the string to variable s_ +
+[green]`abc` +
+`>>>` [blue]`s.1`      [gray]_char at position 1 (starting from 0)_ +
+[green]`b` +
+`>>>` [blue]`s.(-1)`   [gray]_char at position -1, the rightmost one_ +
+[green]`c` +
+`>>>` [blue]`\#s`       [gray]_number of chars_ +
+[gren]`3` +
+`>>>` [blue]`#"abc"`   [gray]_number of chars_ +
+[green]`3` +
 
 === Boolean
 Boolean data type has two values only: _true_ and _false_. Relational and Boolean expressions produce Boolean values.
@@ -300,32 +297,27 @@ The items of array can be accessed using the dot `.` operator.
 ----
 
 .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)`
-[red]`Eval Error: [1:9] index 10 out of bounds`
-`>>>` [blue]`#list`
+`>>>` [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.(10)` +
+[red]`Eval Error: [1:9] index 10 out of bounds` +
+`>>>` [blue]`#list` +
 [green]`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
+.Dictionary examples
 [source,go]
 ----
 {1:"one", 2:"two"}
@@ -336,7 +328,7 @@ The _dictionary_ data-type is set of pairs _key/value_. It is also known as _map
 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.
+A variable is an identifier with an assigned value. Variables are stored in the object that implements the Go _ExprContext_ interface, e.g. _SimpleVarStore_ or _SimpleFuncStore_.
 
 .Examples
 [source,go]
@@ -390,23 +382,30 @@ The _selector operator_ is very similar to the _switch/case/default_ statement a
 <multi-expression> ::= <expression> {";" <expression>}
 ----
 
-In other words, the selector operator evaluates the expression (`<select-expression>`) on the left-hand side of the `?` symbol; it then compares the result obtained with the values listed in the `<match-list>`'s. If the comparision find a match with a value in a match-list, the associated  `<case-multi-expression>` is evaluted, and its result will be the final result of the selection operation.
+In other words, the selector operator evaluates the expression (`<select-expression>`) on the left-hand side of the `?` symbol; it then compares the result obtained with the values listed in the `<match-list>`'s. If the comparision finds a match with a value in a match-list, the associated  `<case-multi-expression>` is evaluted, and its result will be the final result of the selection operation.
 
 The match lists are optional. In that case, the position, from left to right, of the `<selector-case>` is used as match-list. Of course, that only works if the select-expression results in an integer.
 
 The `:` symbol (colon) is the separator of the selector-cases. Note that if the value of the select-expression does not match any match-list, an error will be issued. Therefore, it is strongly recommended to provide a default (multi-)expression introduced by the `::` symbol (double-colon). Also note that the default expression has no match-list.
 
-
 .Examples
 [source,go]
 ----
-1 ? {"a"} : {"b"}                           // returns "b"
-10 ? {"a"} : {"b"} :: {"c"}                 // returns "c"
-10 ? {"a"} :[true, 2+8] {"b"} :: {"c"}      // returns "b"
-10 ? {"a"} :[true, 2+8] {"b"} ::[10] {"c"}  // error:  "... case list in default clause"
-10 ? {"a"} :[10] {x="b" but x} :: {"c"}     // returns "b"
-10 ? {"a"} :[10] {x="b"; x} :: {"c"}        // returns "b"
-10 ? {"a"} : {"b"}                          // error:  "... no case catches the value (10) of the selection expression
+`>>>` [blue]`1 ? {"a"} : {"b"}`
+[green]`b`
+`>>>` [blue]`10 ? {"a"} : {"b"} :: {"c"}`
+[green]`c'
+[green]`>>>` [blue]`10 ? {"a"} :[true, 2+8] {"b"} :: {"c"}`
+[green]`b`
+`>>>` [blue]`10 ? {"a"} :[true, 2+8] {"b"} ::[10] {"c"}`
+[red]`Parse Error: [1:34] case list in default clause`
+[green]`>>>` [blue]`10 ? {"a"} :[10] {x="b" but x} :: {"c"}`
+[green]`b`
+`>>>` [blue]`10 ? {"a"} :[10] {x="b"; x} :: {"c"}`
+[green]`b`
+`>>>` [blue]`10 ? {"a"} : {"b"}`
+[red]`Eval Error: [1:3] no case catches the value (10) of the selection expression`
+
 ----
 
 == Priorities of operators