+
+multi-expression = expression {";" expression }
+TODO: Work in progress (last update on 2024/06/17, 16:31 a.m.)
+TODO: Work in progress (last update on 2024/06/21, 05:40 a.m.)
= returns the value assigned to th
3
>>> x = 5.2 * (9-3) // The assigned value has the approximation error typical of the float data-type
+
>>> x = 5.2 * (9-3) // The assigned value has the typical approximation error of the float data-type
31.200000000000003
= returns the value assigned to th
The semicolon operator ; 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.
multi-expression = expression {";" expression }
+An expression that contains ; is called a multi-expression and each component expressione is called a sub-expression.
; is not treated as a real operator. It ac
>>> 1 ? {"a"} : {"b"}
-b
->>> 10 ? {"a"} : {"b"} :: {"c"}
-c'>>>`
-[green]10 ? {"a"} :[true, 2+8] {"b"} :: {"c"}
-b
->>> 10 ? {"a"} :[true, 2+8] {"b"} ::[10] {"c"}
-Parse Error: [1:34] case list in default clause
->>> 10 ? {"a"} :[10] {x="b" but x} :: {"c"}
-b
->>> 10 ? {"a"} :[10] {x="b"; x} :: {"c"}
-b
->>> 10 ? {"a"} : {"b"}
+b
>>> 10 ? {"a"} : {"b"} :: {"c"}
+c
>>> 10 ? {"a"} :[true, 2+8] {"b"} :: {"c"}
+b
>>> 10 ? {"a"} :[true, 2+8] {"b"} :: [10] {"c"}
+Parse Error: [1:34] case list in default clause
>>> 10 ? {"a"} :[10] {x="b" but x} :: {"c"}
+b
>>> 10 ? {"a"} :[10] {x="b"; x} :: {"c"}
+b
>>> 10 ? {"a"} : {"b"}
Eval Error: [1:3] no case catches the value (10) of the selection expression
?? and ?=The left operand of these two operators must be a variable. The right operator can be any expression. They return the value of the variable if this is define; otherwise they return the value of the right expression.
+The left operand of these two operators must be a variable. The right operator can be any expression. They return the value of the variable if this is defined; otherwise they return the value of the right expression.
| -If the left variable is defined, the right expression is not evuated at all. +If the left variable is defined, the right expression is not evaluated at all. |
The ?? do not change the status of the left variable.
The ?? operator do not change the status of the left variable.
The ?= assigns the calculated value of the right expression to the left variable.
>>> var ?? (1+2)’
-[green]`3
->>> var
-Eval Error: undefined variable or function "var"
->>> var ?= (1+2)
-3
->>> var
+
>>> var ?? (1+2)’
+[green]`3
>>> var
+Eval Error: undefined variable or function "var"
>>> var ?= (1+2)
+3
>>> var
3
iterator ++ → any
DEFAULT
??
Infix
Default value
variable ?? any-expr → any
?=
Infix
Default/assign value
variable ?= any-expr → any
ITER1
()
Prefix
Iterator value
() iterator → any
FACT
!
Postfix
1 Experimental
+In Expr functions compute values in a local context (scope) that do not make effects on the calling context. This is the normal behavior. Using the reference operator @ it is possibile to export local definition to the calling context.
A function is identified and referenced by its name. It can have zero or more parameter. Expr functions also support optional parameters.
+Expr’s function definition syntax
+function-definition = identifier "=" "func(" [param-list] ")" "{" multi-expression "}" +param_list = required-param-list [ "," optional-param-list ] +required-param-list = identifier { "," identifier } +optional-param-list = optional-parm { "," optional-param } +optional-param = identifier "=" any-expr
+TODO
+Description of how to define Golan functions and how to bind them to Expr are topics treated in another document that I’ll write, one day, maybe.
+TODO: function calls operations
TODO: function definitions operations
+Functions compute values in a local context (scope) that do not make effects on the calling context. This is the normal behavior. Using the reference operator @ it is possibile to export local definition to the calling context.