structs

structs - a module to define and manipulate structs

api

creating a constructor

• (struct [type: string] [args: list]) => lambda

testing whether something is a struct

• (struct? [input: any]) => bool

accessing the type and data

• (struct-data [input: struct]) => association-list
• (struct-type [input: struct]) => string

accessing properties

• (struct-props [input: struct]) => list
• (has-prop? [input: struct] [property: any]) => bool
• (get-prop [input: struct] [property: any]) => any
• (set-prop [input: struct] [property: any] [value: any]) => struct

other interesting helpers

for association lists

• (keys [input: association-list]) => list
• (has-key? [input:association-list] [key:any]) => bool
• (zip [list1: list] [list2: list] [[default: any]]) => association-list

for lists

• (extend [list1: list] [list2: list]) => list

general

• `(assert [expr: expression] [message: string]) => ()|panic

usage

(define Person (struct "Person" ["name" "age" "gender"])) ; create a Person struct

(define jeff (Person "Jeff" 25 "Male")) ; jeff is a Person

(struct? jeff) ; => #t
(struct? 123) ; #f

; all structs are associated lists, but not all associated lists are structs
(assoc? jeff) ; => #t
(struct? [["key1" "value1] ["key2" "value2"]]) ; => #f

; access the "type" for comparisons,
; or get the associated-list of the data
(struct-data jeff) ; => (("name" "Jeff") ("age" 25) ("gender" "Male"))
(struct-type jeff) ; => "Person"

(struct-props jeff) ; => ("name" "age" "gender"), like (keys assoc-list)

(has-prop? jeff "name") ; => #t
(has-prop? jeff "occupation") ; => #f
(has-prop? [1 2 3] "name") ; => panic! not a struct

(get-prop jeff "name") ; => "Jeff"
(get-prop jeff "occupation") ; => panic! "occupation" isn't a valid property
(get-prop [1 2 3] "name") ; => panic! not a struct

(set-prop jeff "name" "Jeffrey") ; => a struct like 'jeff' with the altered name
(set-prop [1 2 3] "name" "Jeffrey") ; => panic! not a struct

; structs can't have new properties added to them
(set-prop jeff "occupation" "Programmer") ; => panic! 

; however, they're just associated lists, so this can be worked around
; the below returns what you might expect the above to return
; probably don't do this, though
(assoc jeff STRUCT_DATA (assoc (assoc jeff STRUCT_DATA) "occupation" "Programmer"))