forA more familiar iteration loop to existing developers
This for loop is fills a small niche where foreach or formap idioms will fail within your scripts. It's generally not recommended to use for because it performs slower and doesn't adhere to murex's design philosiphy.
for ( variable; conditional; incrementation ) { code-block } -> <stdout>» for ( i=1; i<6; i++ ) { echo $i }
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5for is a little naughty in terms of breaking murex's style guidelines due to the first parameter being entered as one string treated as 3 separate code blocks. The syntax is like this for two reasons:
{ blocks } would make scripts unsightlyfor loops in other languagesThe first parameter is: ( i=1; i<6; i++ ), but it is then converted into the following code:
let i=0 - declare the loop iteration variable= i<0 - if the condition is true then proceed to run the code in the second parameter - { echo $i }let i++ - increment the loop iteration variableThe second parameter is the code to execute upon each iteration
for loopsBecause each iteration of a for loop reruns the 2nd 2 parts in the first parameter (the conditional and incrementation), for is very slow. Plus the weird, non-idiomatic, way of writing the 3 parts, it's fair to say for is not the recommended method of iteration and in fact there are better functions to achieve the same thing...most of the time at least.
For example:
a: [1..5] -> foreach: i { echo $i }
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5The different in performance can be measured. eg:
» time { a: [1..9999] -> foreach: i { out: <null> $i } }
0.097643108
» time { for ( i=1; i<10000; i=i+1 ) { out: <null> $i } }
0.663812496You can also do step ranges with foreach:
» time { for ( i=10; i<10001; i=i+2 ) { out: <null> $i } }
0.346254973
» time { a: [1..999][0,2,4,6,8],10000 -> foreach i { out: <null> $i } }
0.053924326...though granted the latter is a little less readable.
a (mkarray): A sophisticated yet simple way to build an array or listforeach: Iterate through an arrayif: Conditional statement to execute different blocks of code depending on the result of the conditionja: A sophisticated yet simply way to build a JSON arraylet: Evaluate a mathematical function and assign to variableset: Define a local variable and set it's valuewhile: Loop until condition false