Doc: Fixed a lot of typos
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@ -58,7 +58,7 @@ The expression context is analogous to the stack-frame of other programming lang
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Function contexts are created by cloning the calling context. More details on this topic are given later in this document.
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_Expr_ creates and keeps a inner _global context_ where it stores imported functions, either from builtin or plugin modules. To perform calculations, the calling program must provide its own context; this is the _main context_. All calculations take place in this context. As mentioned eralier, when a function is called, a new context is created by cloning the calling context. The createt context can be called _function context_.
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_Expr_ creates and keeps a inner _global context_ where it stores imported functions, either from builtin or plugin modules. To perform calculations, the calling program must provide its own context; this is the _main context_. All calculations take place in this context. As mentioned eralier, when a function is called, a new context is created by cloning the calling context. The created context can be called _function context_.
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Imported functions are registerd in the _global context_. When an expression first calls an imported function, that function is linked to the current context; this can be the _main context_ or a _function context_.
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@ -321,7 +321,7 @@ Some arithmetic operators can also be used with strings.
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| [blue]`*` | _repeat_ | Make _n_ copy of a string | [blue]`"one" * 2` -> _"oneone"_
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|===
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The items of strings can be accessed using the square `[]` operator.
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The charanters in a string can be accessed using the square `[]` operator.
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.Item access syntax
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====
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@ -340,10 +340,10 @@ The items of strings can be accessed using the square `[]` operator.
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`>>>` [blue]`s[1]` [gray]_// char at position 1 (starting from 0)_ +
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[green]`"b"`
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`>>>` [blue]`s.[-1]` [gray]_// char at position -1, the rightmost one_ +
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`>>>` [blue]`s[-1]` [gray]_// char at position -1, the rightmost one_ +
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[green]`"d"`
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`>>>` [blue]`\#s` [gray]_// number of chars_ +
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`>>>` [blue]`#s` [gray]_// number of chars_ +
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[gren]`4`
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`>>>` [blue]`#"abc"` [gray]_// number of chars_ +
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@ -369,9 +369,9 @@ Boolean data type has two values only: [blue]_true_ and [blue]_false_. Relationa
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| [blue]`\<=` | _Less or Equal_ | True if the left value is less than or equal to the right one | [blue]`5 \<= 2` -> _false_ +
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[blue]`"b" \<= "b"` -> _true_
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| [blue]`>` | _Greater_ | True if the left value is greater than the right one | [blue]`5 > 2` -> _true_ +
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[blue]`"a" < "b"` -> _false_
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[blue]`"a" > "b"` -> _false_
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| [blue]`>=` | _Greater or Equal_ | True if the left value is greater than or equal to the right one | [blue]`5 >= 2` -> _true_ +
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[blue]`"b" \<= "b"` -> _true_
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[blue]`"b" >= "b"` -> _true_
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|===
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^(*)^ See also the [blue]`in` operator in the _list_ and _dictionary_ sections.
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@ -388,7 +388,7 @@ Boolean data type has two values only: [blue]_true_ and [blue]_false_. Relationa
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| [blue]`AND` / [blue]`&&` | _And_ | True if both left and right values are true | [blue]`false && true` -> _false_ +
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[blue]`"a" < "b" AND NOT (2 < 1)` -> _true_
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| [blue]`OR` / [blue]`\|\|` | _Or_ | True if at least one of the left and right values integers true| [blue]`false or true` -> _true_ +
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| [blue]`OR` / [blue]`\|\|` | _Or_ | True if at least one of the left and right values integers is true| [blue]`false or true` -> _true_ +
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[blue]`"a" == "b" OR (2 == 1)` -> _false_
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|===
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@ -413,7 +413,7 @@ _Expr_ supports list of mixed-type values, also specified by normal expressions.
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====
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*_list_* = _empty-list_ | _non-empty-list_ +
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_empty-list_ = "**[]**" +
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_non-empty-list_ = "**[**" _any-value_ {"**,**" _any-value} "**]**" +
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_non-empty-list_ = "**[**" _any-value_ {"**,**" _any-value_} "**]**" +
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====
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.Examples
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@ -459,22 +459,22 @@ Array's items can be accessed using the index `[]` operator.
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====
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.Items of list
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`>>>` [blue]`[1,2,3].1` +
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`>>>` [blue]`[1,2,3][1]` +
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[green]`2`
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`>>>` [blue]`list=[1,2,3]; list.1` +
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`>>>` [blue]`list=[1,2,3]; list[1]` +
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[green]`2`
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`>>>` [blue]`["one","two","three"].1` +
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`>>>` [blue]`["one","two","three"][1]` +
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[green]`two`
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`>>>` [blue]`list=["one","two","three"]; list.(2-1)` +
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`>>>` [blue]`list=["one","two","three"]; list[2-1]` +
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[green]`two`
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`>>>` [blue]`list.(-1)` +
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`>>>` [blue]`list[-1]` +
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[green]`three`
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`>>>` [blue]`list.(10)` +
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`>>>` [blue]`list[10]` +
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[red]`Eval Error: [1:9] index 10 out of bounds`
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`>>>` [blue]`#list` +
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@ -497,7 +497,7 @@ Dictionary literals are sequences of pairs separated by comma [blue]`,` enclosed
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====
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*_dict_* = _empty-dict_ | _non-empty-dict_ +
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_empty-dict_ = "**{}**" +
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_non-empty-dict_ = "**{**" _key-scalar_ "**:**" _any-value_ {"**,**" _key-scalar_ "**:**" _any-value} "**}**" +
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_non-empty-dict_ = "**{**" _key-scalar_ "**:**" _any-value_ {"**,**" _key-scalar_ "**:**" _any-value_} "**}**" +
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====
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@ -551,7 +551,7 @@ NOTE: The assign operator [blue]`=` returns the value assigned to the variable.
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[green]`1`
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`>>>` [blue]`a_b=1+2` +
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[green]`1+2`
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[green]`3`
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`>>>` [blue]`a_b` +
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[green]`3`
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@ -562,7 +562,7 @@ NOTE: The assign operator [blue]`=` returns the value assigned to the variable.
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`>>>` [blue]`x = 1; y = 2*x` +
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[green]`2`
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`>>>` [blue]`_a=2` +
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`>>>` [blue]`\_a=2` +
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[red]`Parse Error: [1:2] unexpected token "_"`
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`>>>` [blue]`1=2` +
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@ -574,12 +574,12 @@ NOTE: The assign operator [blue]`=` returns the value assigned to the variable.
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=== [blue]`;` operator
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The semicolon operator [blue]`;` is an infixed pseudo-operator. It evaluates the left expression first and then the right expression. The value of the latter is the final result.
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.Mult-expression syntax
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.Multi-expression syntax
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====
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*_multi-expression_* = _expression_ {"**;**" _expression_ }
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====
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An expression that contains [blue]`;` is called a _multi-expression_ and each component expressione is called a _sub-expression_.
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An expression that contains [blue]`;` is called a _multi-expression_ and each component expression is called a _sub-expression_.
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IMPORTANT: Technically [blue]`;` is not treated as a real operator. It acts as a separator in lists of expressions.
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@ -589,7 +589,7 @@ TIP: [blue]`;` can be used to set some variables before the final calculation.
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`>>>` [blue]`a=1; b=2; c=3; a+b+c` +
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[green]`6`
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The value of each sub-expression is stored in the automatica variable _last_.
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The value of each sub-expression is stored in the automatic variable _last_.
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.Example
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`>>>` [blue]`2+3; b=last+10; last` +
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@ -600,9 +600,10 @@ The value of each sub-expression is stored in the automatica variable _last_.
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[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.
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.Examples
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[blue]`5 but 2` +
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[green]`2` +
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[blue]`x=2*3 but x-1` +
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`>>>` [blue]`5 but 2` +
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[green]`2`
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`>>>` [blue]`x=2*3 but x-1` +
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[green]`5`.
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[blue]`but` behavior is very similar to [blue]`;`. The only difference is that [blue]`;` is not a true operator and can't be used inside parenthesis [blue]`(` and [blue]`)`.
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@ -610,17 +611,21 @@ The value of each sub-expression is stored in the automatica variable _last_.
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=== Assignment operator [blue]`=`
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The assignment operator [blue]`=` is used to define variables or to change their value in the evaluation context (see _ExprContext_).
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The value on the left side of [blue]`=` must be an identifier. The value on the right side can be any expression and it becomes the result of the assignment operation.
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The value on the left side of [blue]`=` must be a variable identifier or an expression that evalutes to a variable. The value on the right side can be any expression and it becomes the result of the assignment operation.
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.Example
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`>>>` [blue]`a=15+1`
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.Examples
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`>>>` [blue]`a=15+1` +
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[green]`16`
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`>>>` [blue]`L=[1,2,3]; L[1]=5; L` +
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[green]`[1, 5, 3]`
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=== Selector operator [blue]`? : ::`
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The _selector operator_ is very similar to the _switch/case/default_ statement available in many programming languages.
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.Selector literal Syntax
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====
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_selector-operator_ = _select-expression_ "*?*" _selector-case_ { "*:*" _selector-case_ } ["*::*" _default-multi-expression_] +
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_selector-case_ = [_match-list_] _case-value_ +
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_match-list_ = "*[*" _item_ {"*,*" _items_} "*]*" +
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@ -628,6 +633,7 @@ _item_ = _expression_ +
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_case-multi-expression_ = "*{*" _multi-expression_ "*}*" +
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_multi-expression_ = _expression_ { "*;*" _expression_ } +
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_default-multi-expression_ = _multi-expression_
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====
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In other words, the selector operator evaluates the _select-expression_ on the left-hand side of the [blue]`?` symbol; it then compares the result obtained with the values listed in the __match-list__'s, from left to right. 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.
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@ -668,7 +674,7 @@ The [blue]`??` operator do not change the status of the left variable.
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The [blue]`?=` assigns the calculated value of the right expression to the left variable.
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.Examples
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`>>>` [blue]`var ?? (1+2)`' +
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`>>>` [blue]`var ?? (1+2)` +
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[green]`3`
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`>>>` [blue]`var` +
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@ -677,7 +683,7 @@ The [blue]`?=` assigns the calculated value of the right expression to the left
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`>>>` [blue]`var ?= (1+2)` +
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[green]`3`
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`>>>` [blue]`var`
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`>>>` [blue]`var` +
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[green]`3`
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NOTE: These operators have a high priority, in particular higher than the operator [blue]`=`.
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@ -739,21 +745,21 @@ The table below shows all supported operators by decreasing priorities.
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== Functions
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Functions in _Expr_ are very similar to functions available in many programming languages. Actually, _Expr_ supports two types of function, _expr-functions_ and _go-functions_.
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Functions in _Expr_ are very similar to functions available in many programming languages. Currently, _Expr_ supports two types of function, _expr-functions_ and _go-functions_.
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* _expr-functions_ are defined using _Expr_'s syntax. They can be passed as arguments to other functions and can be returned from functions. Moreover, they bind themselves to the defining context, thus becoming closures.
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* _go-functions_ are regular Golang functions callable from _Expr_ expressions. They are defined in Golang source files called _modules_ and compiled within the _Expr_ package. To make Golang functions available in _Expr_ contextes, it is required to _import_ the module in which they are defined.
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* _go-functions_ are regular Golang functions callable from _Expr_ expressions. They are defined in Golang source files called _modules_ and compiled within the _Expr_ package. To make Golang functions available in _Expr_ contextes, it is required to activate the builtin module or to load the plugin module in which they are defined.
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=== _Expr_ function definition
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A function is identified and referenced by its name. It can have zero or more parameter. _Expr_ functions also support optional parameters.
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. Expr's function definition syntax
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.Expr's function definition syntax
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====
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*_function-definition_* = _identifier_ "**=**" "**func(**" [_param-list_] "**)**" "**{**" _multi-expression_ "**}**"
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_param_list_ = _required-param-list_ [ "**,**" _optional-param-list_ ]
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_required-param-list_ = _identifier_ { "**,**" _identifier_ }
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_optional-param-list_ = _optional-parm_ { "**,**" _optional-param_ }
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*_function-definition_* = _identifier_ "**=**" "**func(**" [_param-list_] "**)**" "**{**" _multi-expression_ "**}**" +
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_param_list_ = _required-param-list_ [ "**,**" _optional-param-list_ ] +
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_required-param-list_ = _identifier_ { "**,**" _identifier_ } +
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_optional-param-list_ = _optional-parm_ { "**,**" _optional-param_ } +
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_optional-param_ = _identifier_ "**=**" _any-expr_
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====
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@ -657,7 +657,7 @@ pre.rouge .ss {
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<p>Function contexts are created by cloning the calling context. More details on this topic are given later in this document.</p>
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</div>
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<div class="paragraph">
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<p><em>Expr</em> creates and keeps a inner <em>global context</em> where it stores imported functions, either from builtin or plugin modules. To perform calculations, the calling program must provide its own context; this is the <em>main context</em>. All calculations take place in this context. As mentioned eralier, when a function is called, a new context is created by cloning the calling context. The createt context can be called <em>function context</em>.</p>
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<p><em>Expr</em> creates and keeps a inner <em>global context</em> where it stores imported functions, either from builtin or plugin modules. To perform calculations, the calling program must provide its own context; this is the <em>main context</em>. All calculations take place in this context. As mentioned eralier, when a function is called, a new context is created by cloning the calling context. The created context can be called <em>function context</em>.</p>
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</div>
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<div class="paragraph">
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<p>Imported functions are registerd in the <em>global context</em>. When an expression first calls an imported function, that function is linked to the current context; this can be the <em>main context</em> or a <em>function context</em>.</p>
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@ -1109,7 +1109,7 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
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</tbody>
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</table>
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<div class="paragraph">
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<p>The items of strings can be accessed using the square <code>[]</code> operator.</p>
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<p>The charanters in a string can be accessed using the square <code>[]</code> operator.</p>
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</div>
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<div class="exampleblock">
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<div class="title">Example 4. Item access syntax</div>
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@ -1137,11 +1137,11 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
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<code class="green">"b"</code></p>
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</div>
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<div class="paragraph">
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<p><code>>>></code> <code class="blue">s.[-1]</code> <em class="gray">// char at position -1, the rightmost one</em><br>
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<p><code>>>></code> <code class="blue">s[-1]</code> <em class="gray">// char at position -1, the rightmost one</em><br>
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<code class="green">"d"</code></p>
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</div>
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<div class="paragraph">
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<p><code>>>></code> <code class="blue">\#s</code> <em class="gray">// number of chars</em><br>
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<p><code>>>></code> <code class="blue">#s</code> <em class="gray">// number of chars</em><br>
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<code class="gren">4</code></p>
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</div>
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<div class="paragraph">
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@ -1208,14 +1208,14 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
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<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Greater</em></p></td>
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<td class="tableblock halign-left valign-top"><p class="tableblock">True if the left value is greater than the right one</p></td>
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<td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">5 > 2</code> → <em>true</em><br>
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<code class="blue">"a" < "b"</code> → <em>false</em></p></td>
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<code class="blue">"a" > "b"</code> → <em>false</em></p></td>
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</tr>
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<tr>
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<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">>=</code></p></td>
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<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Greater or Equal</em></p></td>
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<td class="tableblock halign-left valign-top"><p class="tableblock">True if the left value is greater than or equal to the right one</p></td>
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<td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">5 >= 2</code> → <em>true</em><br>
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<code class="blue">"b" <= "b"</code> → <em>true</em></p></td>
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<code class="blue">"b" >= "b"</code> → <em>true</em></p></td>
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</tr>
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</tbody>
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</table>
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@ -1256,7 +1256,7 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
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<tr>
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<td class="tableblock halign-center valign-top"><p class="tableblock"><code class="blue">OR</code> / <code class="blue">||</code></p></td>
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<td class="tableblock halign-center valign-top"><p class="tableblock"><em>Or</em></p></td>
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<td class="tableblock halign-left valign-top"><p class="tableblock">True if at least one of the left and right values integers true</p></td>
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<td class="tableblock halign-left valign-top"><p class="tableblock">True if at least one of the left and right values integers is true</p></td>
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<td class="tableblock halign-left valign-top"><p class="tableblock"><code class="blue">false or true</code> → <em>true</em><br>
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<code class="blue">"a" == "b" OR (2 == 1)</code> → <em>false</em></p></td>
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</tr>
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@ -1314,7 +1314,7 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
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<div class="paragraph">
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<p><strong><em>list</em></strong> = <em>empty-list</em> | <em>non-empty-list</em><br>
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<em>empty-list</em> = "<strong>[]</strong>"<br>
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<em>non-empty-list</em> = "<strong>[</strong>" <em>any-value</em> {"<strong>,</strong>" _any-value} "<strong>]</strong>"<br></p>
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<em>non-empty-list</em> = "<strong>[</strong>" <em>any-value</em> {"<strong>,</strong>" <em>any-value</em>} "<strong>]</strong>"<br></p>
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</div>
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</div>
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</div>
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@ -1416,27 +1416,27 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
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</div>
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<div class="paragraph">
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<div class="title">Items of list</div>
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<p><code>>>></code> <code class="blue">[1,2,3].1</code><br>
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<p><code>>>></code> <code class="blue">[1,2,3][1]</code><br>
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<code class="green">2</code></p>
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</div>
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<div class="paragraph">
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<p><code>>>></code> <code class="blue">list=[1,2,3]; list.1</code><br>
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<p><code>>>></code> <code class="blue">list=[1,2,3]; list[1]</code><br>
|
||||
<code class="green">2</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">["one","two","three"].1</code><br>
|
||||
<p><code>>>></code> <code class="blue">["one","two","three"][1]</code><br>
|
||||
<code class="green">two</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">list=["one","two","three"]; list.(2-1)</code><br>
|
||||
<p><code>>>></code> <code class="blue">list=["one","two","three"]; list[2-1]</code><br>
|
||||
<code class="green">two</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">list.(-1)</code><br>
|
||||
<p><code>>>></code> <code class="blue">list[-1]</code><br>
|
||||
<code class="green">three</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">list.(10)</code><br>
|
||||
<p><code>>>></code> <code class="blue">list[10]</code><br>
|
||||
<code class="red">Eval Error: [1:9] index 10 out of bounds</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
@ -1466,7 +1466,7 @@ dev-expr <span class="nt">--</span> Expressions calculator v1.10.0<span class="o
|
||||
<div class="paragraph">
|
||||
<p><strong><em>dict</em></strong> = <em>empty-dict</em> | <em>non-empty-dict</em><br>
|
||||
<em>empty-dict</em> = "<strong>{}</strong>"<br>
|
||||
<em>non-empty-dict</em> = "<strong>{</strong>" <em>key-scalar</em> "<strong>:</strong>" <em>any-value</em> {"<strong>,</strong>" <em>key-scalar</em> "<strong>:</strong>" _any-value} "<strong>}</strong>"<br></p>
|
||||
<em>non-empty-dict</em> = "<strong>{</strong>" <em>key-scalar</em> "<strong>:</strong>" <em>any-value</em> {"<strong>,</strong>" <em>key-scalar</em> "<strong>:</strong>" <em>any-value</em>} "<strong>}</strong>"<br></p>
|
||||
</div>
|
||||
</div>
|
||||
</div>
|
||||
@ -1575,7 +1575,7 @@ The assign operator <code class="blue">=</code> returns the value assigned to th
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">a_b=1+2</code><br>
|
||||
<code class="green">1+2</code></p>
|
||||
<code class="green">3</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">a_b</code><br>
|
||||
@ -1590,8 +1590,8 @@ The assign operator <code class="blue">=</code> returns the value assigned to th
|
||||
<code class="green">2</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue"><em>a=2</code><br>
|
||||
<code class="red">Parse Error: [1:2] unexpected token "</em>"</code></p>
|
||||
<p><code>>>></code> <code class="blue">_a=2</code><br>
|
||||
<code class="red">Parse Error: [1:2] unexpected token "_"</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">1=2</code><br>
|
||||
@ -1608,7 +1608,7 @@ The assign operator <code class="blue">=</code> returns the value assigned to th
|
||||
<p>The semicolon operator <code class="blue">;</code> is an infixed pseudo-operator. It evaluates the left expression first and then the right expression. The value of the latter is the final result.</p>
|
||||
</div>
|
||||
<div class="exampleblock">
|
||||
<div class="title">Example 12. Mult-expression syntax</div>
|
||||
<div class="title">Example 12. Multi-expression syntax</div>
|
||||
<div class="content">
|
||||
<div class="paragraph">
|
||||
<p><strong><em>multi-expression</em></strong> = <em>expression</em> {"<strong>;</strong>" <em>expression</em> }</p>
|
||||
@ -1616,7 +1616,7 @@ The assign operator <code class="blue">=</code> returns the value assigned to th
|
||||
</div>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p>An expression that contains <code class="blue">;</code> is called a <em>multi-expression</em> and each component expressione is called a <em>sub-expression</em>.</p>
|
||||
<p>An expression that contains <code class="blue">;</code> is called a <em>multi-expression</em> and each component expression is called a <em>sub-expression</em>.</p>
|
||||
</div>
|
||||
<div class="admonitionblock important">
|
||||
<table>
|
||||
@ -1648,7 +1648,7 @@ Technically <code class="blue">;</code> is not treated as a real operator. It ac
|
||||
<code class="green">6</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p>The value of each sub-expression is stored in the automatica variable <em>last</em>.</p>
|
||||
<p>The value of each sub-expression is stored in the automatic variable <em>last</em>.</p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<div class="title">Example</div>
|
||||
@ -1663,9 +1663,11 @@ Technically <code class="blue">;</code> is not treated as a real operator. It ac
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<div class="title">Examples</div>
|
||||
<p><code class="blue">5 but 2</code><br>
|
||||
<code class="green">2</code><br>
|
||||
<code class="blue">x=2*3 but x-1</code><br>
|
||||
<p><code>>>></code> <code class="blue">5 but 2</code><br>
|
||||
<code class="green">2</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">x=2*3 but x-1</code><br>
|
||||
<code class="green">5</code>.</p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
@ -1678,21 +1680,27 @@ Technically <code class="blue">;</code> is not treated as a real operator. It ac
|
||||
<p>The assignment operator <code class="blue">=</code> is used to define variables or to change their value in the evaluation context (see <em>ExprContext</em>).</p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p>The value on the left side of <code class="blue">=</code> must be an identifier. The value on the right side can be any expression and it becomes the result of the assignment operation.</p>
|
||||
<p>The value on the left side of <code class="blue">=</code> must be a variable identifier or an expression that evalutes to a variable. The value on the right side can be any expression and it becomes the result of the assignment operation.</p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<div class="title">Example</div>
|
||||
<p><code>>>></code> <code class="blue">a=15+1</code>
|
||||
<div class="title">Examples</div>
|
||||
<p><code>>>></code> <code class="blue">a=15+1</code><br>
|
||||
<code class="green">16</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">L=[1,2,3]; L[1]=5; L</code><br>
|
||||
<code class="green">[1, 5, 3]</code></p>
|
||||
</div>
|
||||
</div>
|
||||
<div class="sect2">
|
||||
<h3 id="_selector_operator"><a class="anchor" href="#_selector_operator"></a><a class="link" href="#_selector_operator">4.4. Selector operator <code class="blue">? : ::</code></a></h3>
|
||||
<div class="paragraph">
|
||||
<p>The <em>selector operator</em> is very similar to the <em>switch/case/default</em> statement available in many programming languages.</p>
|
||||
</div>
|
||||
<div class="exampleblock">
|
||||
<div class="title">Example 13. Selector literal Syntax</div>
|
||||
<div class="content">
|
||||
<div class="paragraph">
|
||||
<div class="title">Selector literal Syntax</div>
|
||||
<p><em>selector-operator</em> = <em>select-expression</em> "<strong>?</strong>" <em>selector-case</em> { "<strong>:</strong>" <em>selector-case</em> } ["<strong>::</strong>" <em>default-multi-expression</em>]<br>
|
||||
<em>selector-case</em> = [<em>match-list</em>] <em>case-value</em><br>
|
||||
<em>match-list</em> = "<strong>[</strong>" <em>item</em> {"<strong>,</strong>" <em>items</em>} "<strong>]</strong>"<br>
|
||||
@ -1701,6 +1709,8 @@ Technically <code class="blue">;</code> is not treated as a real operator. It ac
|
||||
<em>multi-expression</em> = <em>expression</em> { "<strong>;</strong>" <em>expression</em> }<br>
|
||||
<em>default-multi-expression</em> = <em>multi-expression</em></p>
|
||||
</div>
|
||||
</div>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p>In other words, the selector operator evaluates the <em>select-expression</em> on the left-hand side of the <code class="blue">?</code> symbol; it then compares the result obtained with the values listed in the <em>match-list</em>'s, from left to right. If the comparision finds a match with a value in a <em>match-list</em>, the associated <em>case-multi-expression</em> is evaluted, and its result will be the final result of the selection operation.</p>
|
||||
</div>
|
||||
@ -1765,8 +1775,8 @@ If the left variable is defined, the right expression is not evaluated at all.
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<div class="title">Examples</div>
|
||||
<p><code>>>></code> <code class="blue">var ?? (1+2)’<br>
|
||||
[green]`3</code></p>
|
||||
<p><code>>>></code> <code class="blue">var ?? (1+2)</code><br>
|
||||
<code class="green">3</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">var</code><br>
|
||||
@ -1777,7 +1787,7 @@ If the left variable is defined, the right expression is not evaluated at all.
|
||||
<code class="green">3</code></p>
|
||||
</div>
|
||||
<div class="paragraph">
|
||||
<p><code>>>></code> <code class="blue">var</code>
|
||||
<p><code>>>></code> <code class="blue">var</code><br>
|
||||
<code class="green">3</code></p>
|
||||
</div>
|
||||
<div class="admonitionblock note">
|
||||
@ -2106,7 +2116,7 @@ These operators have a high priority, in particular higher than the operator <co
|
||||
<h2 id="_functions"><a class="anchor" href="#_functions"></a><a class="link" href="#_functions">6. Functions</a></h2>
|
||||
<div class="sectionbody">
|
||||
<div class="paragraph">
|
||||
<p>Functions in <em>Expr</em> are very similar to functions available in many programming languages. Actually, <em>Expr</em> supports two types of function, <em>expr-functions</em> and <em>go-functions</em>.</p>
|
||||
<p>Functions in <em>Expr</em> are very similar to functions available in many programming languages. Currently, <em>Expr</em> supports two types of function, <em>expr-functions</em> and <em>go-functions</em>.</p>
|
||||
</div>
|
||||
<div class="ulist">
|
||||
<ul>
|
||||
@ -2114,7 +2124,7 @@ These operators have a high priority, in particular higher than the operator <co
|
||||
<p><em>expr-functions</em> are defined using <em>Expr</em>'s syntax. They can be passed as arguments to other functions and can be returned from functions. Moreover, they bind themselves to the defining context, thus becoming closures.</p>
|
||||
</li>
|
||||
<li>
|
||||
<p><em>go-functions</em> are regular Golang functions callable from <em>Expr</em> expressions. They are defined in Golang source files called <em>modules</em> and compiled within the <em>Expr</em> package. To make Golang functions available in <em>Expr</em> contextes, it is required to <em>import</em> the module in which they are defined.</p>
|
||||
<p><em>go-functions</em> are regular Golang functions callable from <em>Expr</em> expressions. They are defined in Golang source files called <em>modules</em> and compiled within the <em>Expr</em> package. To make Golang functions available in <em>Expr</em> contextes, it is required to activate the builtin module or to load the plugin module in which they are defined.</p>
|
||||
</li>
|
||||
</ul>
|
||||
</div>
|
||||
@ -2123,20 +2133,14 @@ These operators have a high priority, in particular higher than the operator <co
|
||||
<div class="paragraph">
|
||||
<p>A function is identified and referenced by its name. It can have zero or more parameter. <em>Expr</em> functions also support optional parameters.</p>
|
||||
</div>
|
||||
<div class="olist arabic">
|
||||
<ol class="arabic">
|
||||
<li>
|
||||
<p>Expr’s function definition syntax</p>
|
||||
</li>
|
||||
</ol>
|
||||
</div>
|
||||
<div class="exampleblock">
|
||||
<div class="title">Example 14. Expr’s function definition syntax</div>
|
||||
<div class="content">
|
||||
<div class="paragraph">
|
||||
<p><strong><em>function-definition</em></strong> = <em>identifier</em> "<strong>=</strong>" "<strong>func(</strong>" [<em>param-list</em>] "<strong>)</strong>" "<strong>{</strong>" <em>multi-expression</em> "<strong>}</strong>"
|
||||
<em>param_list</em> = <em>required-param-list</em> [ "<strong>,</strong>" <em>optional-param-list</em> ]
|
||||
<em>required-param-list</em> = <em>identifier</em> { "<strong>,</strong>" <em>identifier</em> }
|
||||
<em>optional-param-list</em> = <em>optional-parm</em> { "<strong>,</strong>" <em>optional-param</em> }
|
||||
<p><strong><em>function-definition</em></strong> = <em>identifier</em> "<strong>=</strong>" "<strong>func(</strong>" [<em>param-list</em>] "<strong>)</strong>" "<strong>{</strong>" <em>multi-expression</em> "<strong>}</strong>"<br>
|
||||
<em>param_list</em> = <em>required-param-list</em> [ "<strong>,</strong>" <em>optional-param-list</em> ]<br>
|
||||
<em>required-param-list</em> = <em>identifier</em> { "<strong>,</strong>" <em>identifier</em> }<br>
|
||||
<em>optional-param-list</em> = <em>optional-parm</em> { "<strong>,</strong>" <em>optional-param</em> }<br>
|
||||
<em>optional-param</em> = <em>identifier</em> "<strong>=</strong>" <em>any-expr</em></p>
|
||||
</div>
|
||||
</div>
|
||||
@ -2200,7 +2204,7 @@ These operators have a high priority, in particular higher than the operator <co
|
||||
</div>
|
||||
<div id="footer">
|
||||
<div id="footer-text">
|
||||
Last updated 2024-06-21 09:06:12 +0200
|
||||
Last updated 2024-09-12 06:56:30 +0200
|
||||
</div>
|
||||
</div>
|
||||
</body>
|
||||
|
||||
Loading…
Reference in New Issue
Block a user