Standard Library — Prelude

Prelude

The Prelude is LOVE-LANG’s standard library module that is automatically available to all programmes. Import it with:

@Import[Prelude::*]

---

Core Values

Name	Type	Value	Description
true	Boolean	true	Boolean truth
false	Boolean	false	Boolean falsity
nil	Nil	nil	The null value
inf	Number	∞	Positive infinity

---

Arithmetic (L2)

sum     = [[ + 1 2 3 ]]        # 6
diff    = [[ - 10 3 ]]         # 7
product = [[ * 4 5 ]]          # 20
ratio   = [[ / 10 2 ]]         # 5
mod     = [[ % 10 3 ]]         # 1
power   = [[ ** 2 8 ]]         # 256

Function	Arity	Description
+	n	Sum of all arguments
-	2	Subtraction
*	n	Product of all arguments
/	2	Division
%	2	Modulo
**	2	Exponentiation
Math.sqrt	1	Square root
Math.abs	1	Absolute value
Math.max	n	Maximum value
Math.min	n	Minimum value
Math.floor	1	Floor
Math.ceil	1	Ceiling
Math.round	1	Round to nearest integer

---

String Operations (L2)

joined  = [[ String.concat "Hello, " name ]]
upper   = [[ String.upper "love" ]]
lower   = [[ String.lower "LOVE" ]]
trimmed = [[ String.trim "  love  " ]]
length  = [[ String.length "LOVE-LANG" ]]
csv     = [[ String.join "," ["a" "b" "c"] ]]

Function	Arity	Description
String.concat	n	Concatenate strings
String.upper	1	Uppercase
String.lower	1	Lowercase
String.trim	1	Trim whitespace
String.length	1	String length
String.join	2	Join list with separator
String.split	2	Split by separator
String.contains?	2	Substring check
String.starts-with?	2	Prefix check
String.ends-with?	2	Suffix check
String.from-number	1	Convert number to string
Number.from-string	1	Parse number from string

---

List Operations (L2)

mapped    = [[ List.map double [1 2 3] ]]
filtered  = [[ List.filter positive? [1 -2 3 -4] ]]
folded    = [[ List.fold + 0 [1 2 3 4 5] ]]
flattened = [[ List.flatten [[1 2] [3 4]] ]]
reversed  = [[ List.reverse [1 2 3] ]]

Function	Arity	Description
List.map	2	Apply function to each element
List.filter	2	Keep elements matching predicate
List.fold	3	Fold list with accumulator
List.flatten	1	Flatten nested list
List.reverse	1	Reverse list
List.length	1	List length
List.first	1	First element
List.last	1	Last element
List.rest	1	All but first
List.take	2	Take N elements
List.drop	2	Drop N elements
List.contains?	2	Membership check
List.unique	1	Remove duplicates
List.sort	1	Sort ascending
List.zip	2	Zip two lists

---

Logic (L2)

all-true = [[ @and [true true true] ]]
any-true = [[ @or  [false true false] ]]
negated  = [[ not true ]]
equal    = [[ = 1 1 ]]

Function	Arity	Description
@and	n	All truthy
@or	n	Any truthy
not	1	Boolean negation
=	2	Equality
!=	2	Inequality
>	2	Greater than
<	2	Less than
>=	2	Greater than or equal
<=	2	Less than or equal

---

I/O Effectors (L5)

These must be declared in model.edn before use:

[[[[[
  @print "Hello, World!"
]]]]]

[[[[[
  @println "Line with newline"
]]]]]

Effector	Arity	Description
@print	1	Print to stdout
@println	1	Print with newline
@read-file	1	Read file contents
@write-file	2	Write string to file
@http-get	1	HTTP GET request
@http-post	2	HTTP POST request
@sql-write	2	Database write
@sql-read	2	Database query