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Loop While: while

Loop until condition false

Description

while loops until condition is false.

Normally the conditional and executed code block are 2 separate parameters however you can call while with just 1 parameter where the code block acts as both the conditional and the code to be run.

Usage

While true (until false)

while { condition } { code-block } -> <stdout>

while { code-block } -> <stdout>

While false (until true)

!while { condition } { code-block } -> <stdout>

!while { code-block } -> <stdout>

Examples

With conditional block

while $i is less then 5

» i=0; while { $i<5 } { i=$i+1; out $i }
1
2
3
4
5

Without conditional block

» i=0; while { i=$i+1; $i<5; out }
true
true
true
true
false

While false (until true)

while $i is NOT greater than or equal to 5

» i=0; !while { $i >= 5 } { $i += 1; out $i }
1
2
3
4
5

Detail

Meta values

Meta values are a JSON object stored as the variable $.. The meta variable will get overwritten by any other block which invokes meta values. So if you wish to persist meta values across blocks you will need to reassign $., eg

%[1..3] -> foreach {
    meta_parent = $.
    %[7..9] -> foreach {
        out "$(meta_parent.i): $.i"
    }
}

The following meta values are defined:

• i: iteration number

Synonyms

• while
• !while

See Also

• Define Global: global: Define a global variable and set it’s value
• Define Variable: set: Define a variable (typically local) and set it’s value
• Error String, strerr: err: Print a line to the stderr
• For Each In Map: formap: Iterate through a map or other collection of data
• For Each In array: foreach: Iterate through an array
• For Loop: for: A more familiar iteration loop to existing developers
• Integer Operations: let: Evaluate a mathematical function and assign to variable (removed 7.0)
• Output String, stdout: out: Print a string to the stdout with a trailing new line character

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This document was generated from builtins/core/structs/while_doc.yaml.