Aiagent: Created page with "= Lists = The '''Lists''' module provides comprehensive list manipulation and processing functions for the SCM programming language. This module includes: * '''List operations''': Basic operations like counting (count), accessing elements (nth), and type checking (list?) * '''List construction''': Building lists with append, cons, and unique operations (append_unique, merge_unique) * '''List deconstruction''': Extracting parts with car (head), cdr (tail), and filtering..."

2025-08-25T16:46:21Z

Created page with "= Lists = The '''Lists''' module provides comprehensive list manipulation and processing functions for the SCM programming language. This module includes: * '''List operations''': Basic operations like counting (count), accessing elements (nth), and type checking (list?) * '''List construction''': Building lists with append, cons, and unique operations (append_unique, merge_unique) * '''List deconstruction''': Extracting parts with car (head), cdr (tail), and filtering..."

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= Lists =

The '''Lists''' module provides comprehensive list manipulation and processing functions for the SCM programming language. This module includes:

* '''List operations''': Basic operations like counting (count), accessing elements (nth), and type checking (list?)
* '''List construction''': Building lists with append, cons, and unique operations (append_unique, merge_unique)
* '''List deconstruction''': Extracting parts with car (head), cdr (tail), and filtering operations
* '''Functional programming''': Higher-order functions like map, filter, reduce, and produce for advanced list processing
* '''List utilities''': Searching (has?, contains?), merging, zipping, and flattening operations
* '''List generation''': Creating sequences and ranges with produce and produceN functions

These functions provide the essential tools for working with lists as the primary data structure in functional programming with SCM.

← Back to [[Full SCM API documentation]]

== count ==

counts the number of elements in the list

'''Allowed number of parameters:''' 1–1

'''Parameters:'''
* '''list''' (<code>list</code>): base list

'''Returns:''' <code>int</code>

== nth ==

get the nth item of a list

'''Allowed number of parameters:''' 2–2

'''Parameters:'''
* '''list''' (<code>list</code>): base list
* '''index''' (<code>number</code>): index beginning from 0

'''Returns:''' <code>any</code>

== append ==

appends items to a list and return the extended list. The original list stays unharmed.

'''Allowed number of parameters:''' 2–1000

'''Parameters:'''
* '''list''' (<code>list</code>): base list
* '''item...''' (<code>any</code>): items to add

'''Returns:''' <code>list</code>

== append_unique ==

appends items to a list but only if they are new. The original list stays unharmed.

'''Allowed number of parameters:''' 2–1000

'''Parameters:'''
* '''list''' (<code>list</code>): base list
* '''item...''' (<code>any</code>): items to add

'''Returns:''' <code>list</code>

== cons ==

constructs a list from a head and a tail list

'''Allowed number of parameters:''' 2–2

'''Parameters:'''
* '''car''' (<code>any</code>): new head element
* '''cdr''' (<code>list</code>): tail that is appended after car

'''Returns:''' <code>list</code>

== car ==

extracts the head of a list

'''Allowed number of parameters:''' 1–1

'''Parameters:'''
* '''list''' (<code>list</code>): list

'''Returns:''' <code>any</code>

== cdr ==

extracts the tail of a list. The tail of a list is a list with all items except the head.

'''Allowed number of parameters:''' 1–1

'''Parameters:'''
* '''list''' (<code>list</code>): list

'''Returns:''' <code>any</code>

== zip ==

swaps the dimension of a list of lists. If one parameter is given, it is a list of lists that is flattened. If multiple parameters are given, they are treated as the components that will be zipped into the sub list

'''Allowed number of parameters:''' 1–1000

'''Parameters:'''
* '''list''' (<code>list</code>): list of lists of items

'''Returns:''' <code>list</code>

== merge ==

flattens a list of lists into a list containing all the subitems. If one parameter is given, it is a list of lists that is flattened. If multiple parameters are given, they are treated as lists that will be merged into one

'''Allowed number of parameters:''' 1–1000

'''Parameters:'''
* '''list''' (<code>list</code>): list of lists of items

'''Returns:''' <code>list</code>

== merge_unique ==

flattens a list of lists into a list containing all the subitems. Duplicates are filtered out.

'''Allowed number of parameters:''' 1–1000

'''Parameters:'''
* '''list''' (<code>list</code>): list of lists of items

'''Returns:''' <code>list</code>

== has? ==

checks if a list has a certain item (equal?)

'''Allowed number of parameters:''' 2–2

'''Parameters:'''
* '''haystack''' (<code>list</code>): list to search in
* '''needle''' (<code>any</code>): item to search for

'''Returns:''' <code>bool</code>

== filter ==

returns a list that only contains elements that pass the filter function

'''Allowed number of parameters:''' 2–2

'''Parameters:'''
* '''list''' (<code>list</code>): list that has to be filtered
* '''condition''' (<code>func</code>): filter condition func(any)->bool

'''Returns:''' <code>list</code>

== map ==

returns a list that contains the results of a map function that is applied to the list

'''Allowed number of parameters:''' 2–2

'''Parameters:'''
* '''list''' (<code>list</code>): list that has to be mapped
* '''map''' (<code>func</code>): map function func(any)->any that is applied to each item

'''Returns:''' <code>list</code>

== mapIndex ==

returns a list that contains the results of a map function that is applied to the list

'''Allowed number of parameters:''' 2–2

'''Parameters:'''
* '''list''' (<code>list</code>): list that has to be mapped
* '''map''' (<code>func</code>): map function func(i, any)->any that is applied to each item

'''Returns:''' <code>list</code>

== reduce ==

returns a list that contains the result of a map function

'''Allowed number of parameters:''' 2–3

'''Parameters:'''
* '''list''' (<code>list</code>): list that has to be reduced
* '''reduce''' (<code>func</code>): reduce function func(any any)->any where the first parameter is the accumulator, the second is a list item
* '''neutral''' (<code>any</code>): (optional) initial value of the accumulator, defaults to nil

'''Returns:''' <code>any</code>

== produce ==

returns a list that contains produced items - it works like for(state = startstate, condition(state), state = iterator(state)) {yield state}

'''Allowed number of parameters:''' 3–3

'''Parameters:'''
* '''startstate''' (<code>any</code>): start state to begin with
* '''condition''' (<code>func</code>): func that returns true whether the state will be inserted into the result or the loop is stopped
* '''iterator''' (<code>func</code>): func that produces the next state

'''Returns:''' <code>list</code>

== produceN ==

returns a list with numbers from 0..n-1

'''Allowed number of parameters:''' 1–1

'''Parameters:'''
* '''n''' (<code>number</code>): number of elements to produce

'''Returns:''' <code>list</code>

== list? ==

checks if a value is a list

'''Allowed number of parameters:''' 1–1

'''Parameters:'''
* '''value''' (<code>any</code>): value to check

'''Returns:''' <code>bool</code>

== contains? ==

checks if a value is in a list; uses the equal?? operator

'''Allowed number of parameters:''' 2–2

'''Parameters:'''
* '''list''' (<code>list</code>): list to check
* '''value''' (<code>any</code>): value to check

'''Returns:''' <code>bool</code>

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