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5.2 Functions
Here is an exhaustive description of the functions provided by LispE.
Returns the value corresponding to a sequence of keys. The container can be a list, a matrix, a tensor or a dictionary.
(setq r (rho 2 2 (iota 5))) ; r = ((1 2) (3 4))
(println (@ r 0 1)) ; is 2This operator is a synonym of extract
This operator is a synonym of atshape
Boolean AND
(and (< 10 100) (>= 10 10)) ; gives true Boolean AND that returns a value
(andvalue (< 10 100) (>= 10 10) 21) ; returns 21applies a function to the following arguments
(apply '+ '(1 2 3 4)) ; gives 10
(setq f '*)
(apply f '(2 3 4)) ; gives 24Returns the value corresponding to a sequence of keys. The container can be a list, a matrix, a tensor or a dictionary.
at is the official name for the operator @
(setq r (rho 2 2 (iota 5))) ; r = ((1 2) (3 4))
(println (at r 0 1)) ; is 2Returns the value corresponding to a sequence of keys, according to a shape. The container should be a flat list of values. shape should be a list of values that provides the virtual dimensions that are projected onto the flat list of values.
When keys are negative then LispE iterates on all lines or columns.
- if key is -1 then it iterates on lines.
- if key is -2 then it iterates on columns.
Important: If you interpolate negative and positive dimensions, the result is unpredictable. Negative dimensions should always be together. The line or column extraction is defined by the last negative key.
atshape is the official name for the operator @@@
(setq fv (range 0 60 1))
(setq sh (integers 3 4 5))
(@@@ fv sh 1 2 3) ;33
(@@@ fv sh 1 2) ;(30,31,32,33,34)
(@@@ fv sh -1 -1 1) ;(1,6,11,16,21,26,31,36,41,46,51,56)
(@@@ fv sh -1 -2 1) ;(1 21 41 6 26 46 11 31 51 16 36 56)
(@@@ fv sh -1 -1) ;(0..59)
(@@@ fv sh -1 -2) ;(0,1,2,3,4,20,21,22,23,24,40,41,42,43,44,5,6,7,8,9,25,26,27,28,29,45,46,47,48,49...)
returns true if the argument is an atom
(atomp 'e) ; returns truereturns the list of atoms stored at the top of the execution stack
(atoms) ; at the root returns:
(fpiecewise_linear_distribution piecewise_constant_distribution discrete_distribution log cosh cos cbrt asin alphap second hour etc.).allows the evaluation of a list of lists
(if (eq x 10)
(block
(print x)
1
)
(+ x 1)
)__root__ is a specific kind of block, which is used to enclose the initial code before evaluation.
Basically, we use this instruction to push the whole code within a single block.
This instruction is usually hidden within LispE's compiler, however it can be used in some cases when evaluating a block of instructions.
Returns the list of bodies for defpat function definitions
Allows you to exit a "loop".
- car returns the first element of a list
- cdr returns the list following the first item.
Variations can also be made by mixing the a and r. For example caadr corresponds to (car (car (cdr l))).
(car '(1 2 3)) ; gives 1
(cdr '(1 2 3)) ; gives '(2 3))
(cdar '((1 5) 2 3)) ; gives (5) equivalent to (cdr (car '((1 5) 2 3)))
Appends a list of shorts to a file, byte by byte.
reads a text file (UTF8) and returns the content as a list of shorts.
Writes a list of shorts to a file, byte by byte.
This method returns the content of a string as a list of shorts, corresponding to the internal encoding of the string.
(setq s b"This is a string")
(bytes s) ; (84 104 105 115 32 105 115 32 97 32 115 116 114 105 110 103)catch is used to capture errors as a way to prevent programs from stopping.
catch acts as a block. It takes a list of instructions and stops at the first error. It then returns a maybe object that contains the error message. You can then use the instruction maybe to check if an error occurred while running the code.
(setq c
(catch
(setq e 10)
(setq v 0)
(cons ' a)
)
)
(if
(maybe c)
(print Error: c)
(print No error)
)If CONDITION is true, execute the list of instructions: I1,I2... to In.
(setq k 10)
; if k < 100, we increment it
(check (< k 100)
(println k)
(+= k 1)
)
Clones a container or a string.
This instruction is used to create complex numbers. It takes two arguments of type number to create a complex number.
A complex number can also be created with the following pattern: r,ni, where is r and n are actual values.
Complex numbers can be used in any types of numerical expressions.
It is possible to extract the real and the imaginary part with the function: real and imaginary.
;These two instructions are equivalent
(setq c (complex 10 -3))
(setq cc 10,-3i)
Allows to chain multiple conditions
(cond
(
(< x 10)
(print x is smaller than 10)
)
(
(< x 100)
(print x is smaller than 100)
)
(true
(print x is greater than 100)
)
)It creates a new list by merging the first item into the next one.
(cons 'a ()) ; gives (a)consb works as a reverse cons.
(consb means cons_back)
It creates a new list with the first element as the initial list.
; Compares cons to consb on a simple example
(cons '(a b) '(c d)); is ((a b) c d)
(consb '(a b) '(c d)); is (a b (c d))returns true if the argument is a list
(consp '(1 2 3)) ; returns true Returns the keys of a container. Same as keys@
(print (containerkeys d)) Returns values from a dictionary (see containerkeys)
Same as values@
Counts the number of times u is in o
(count "abcdefabdefabghabtr" "ab") ; yields 4This instruction slices a list or a string into a list of slices of same size.
(see slice for the original name)
(cutlist '(a b c d e f g h i j k l) 3) ; ((a b c) (d e f) (g h i) (j k l))returns true if the argument is a linked list that contains cycles
(setq l (llist 10 20 30))
(extend l l)
(cyclicp l) ; yields truedata is used to defined data structures, which can be used to organise data and types.
see: Data Structures for more information.
defmacro helps define your own macros. A macro is a piece of code that is replaced on the fly within your functions. When you use a macro, there is no call to a function, since the code has been replaced with the macro instructions.
Note: You can use any variable names in the macros. Actually, when the macro is compiled, its variable names are replaced with specific macro names that cannot be confused with LispE declarable names.
; this macro returns true if a value is in a list
(defmacro in_list (x l) (not (nullp (find l x))))
; You simply use the name as if it was a function name.
(println (in_list 1 '(1 2 3 4)))
; whose underlying structure is now:
(println (not (nullp (find '(1 2 3 4) 1))))see: Macro Functions for more information.
see Enrich LispE
allows you to define a function. defun consists of a name followed by a list of arguments and the body of the function.
(defun add (x y) (+ x y))allows you to define pattern matching functions. Note that the function name can be defined more than once, each with a different pattern.
see: Pattern Functions for more information.
defpred is a function definition mechanism in LispE that extends pattern matching with predicate-based function selection, pred stands for predicate in this context. Similar to defpat, it allows multiple function definitions with the same name that are selected based on pattern matching.
Key Differences from defpat:
- In
defpred, each instruction in the function body is evaluated as a Boolean - If any instruction returns false (nil or 0), the function fails
- Upon failure, the system attempts the next function definition
- Provides built-in backtracking similar to Prolog's logical programming approach
Parameter Matching:
- Supports type-based and pattern-based parameter matching like
defpat - Uses the same parameter definition rules
- Can match against lists, dictionaries, and custom data types
Execution Behavior:
- Functions are tried in order of definition
- Each function body is a series of boolean tests
- Successful execution stops further function searching
- Failed tests trigger searching for alternative function definitions
(defpred teste ([])
true
)
(defpred teste ([a $ b])
(< a 10)
(println a)
(teste b)
)
(defpred teste (l)
(println "We stop" l)
)
(teste '(1 2 11 12 13))
; yields
1
2
We stop (11 12 13)dethread allows you to declare a thread. The main thread can then wait for all these threads to end their execution.
; we define a thread
(dethread call(s i)
(loop e (range 0 i 1)
(+= s (string e))
)
(println s)
)
; We call 3 threads with different arguments
(call "l:" 10)
(call "x:" 20)
(call "y:" 30)
; we wait for these threads to end
(wait)defspace defines a namespace, in which every function defined in the body is stored.
These functions can only be accessed with the space operator.
Note: namespace is always an atom.
A namespace is a way to ensure that different function implementation sharing the same name can coexist in the same program.
A namespace can be created with defspace but also load or use. Thanks to namespace, function name collisions can then be avoided.
(defspace truc
(defun calculus (x y)
(+ x y)
)
(defun toto (u v)
(* u v)
)
)
(println (space truc (calculus 10 20)))(dictionary k v k' v' k" v"...): Creates a dictionary with key/value couples
; We create a dictionary
(setq d (dictionary "a" "e" "b" "c" "d" "e"))
; We display the value for the key "a".
(println (@ d "a"))(dictionaryi k v k' v' k" v"...): Creates a dictionary with key/value couples
; We create a dictionary
(setq d (dictionaryi 12 "e" 17 "b" 15 "hh"))
; We display the value for the key 12.
(println (@ d 12))(dictionaryn k v k' v' k" v"...): Creates a dictionary with key/value couples
; We create a dictionary
(setq d (dictionaryn 12 "e" 17 "b" 15 "hh"))
; We display the value for the key 12.
(println (@ d 12))(dictionarytree k v k' v' k" v"...): Creates a dictionary with key/value couples
; We create a dictionary
(setq d (dictionarytree "a" "e" "b" "c" "d" "e"))
; We display the value for the key "a".
(println (@ d "a"))(dictionarytreei k v k' v' k" v"...): Creates a dictionary with key/value couples
; We create a dictionary
(setq d (dictionarytreei 12 "e" 17 "b" 15 "hh"))
; We display the value for the key 12.
(println (@ d 12))(dictionarytreen k v k' v' k" v"...): Creates a dictionary with key/value couples
; We create a dictionary
(setq d (dictionarytreen 12 "e" 17 "b" 15 "hh"))
; We display the value for the key 12.
(println (@ d 12))- This function is very similar to dropwhile however, it cannot compose with other high level functions such as map, takewhile or drop.
- Second, the value from the list is always appended at the end of the condition, unless you use
_as a slot filler.
As such, it is not expanded into a loop instruction as dropwhile and is much faster.
droplist drops elements from a list until the condition complies with a value. It then returns the remainder of the list.
(droplist '(< 10) '(1 4 5 11 9 11 20)) returns (11 9 11 20) ; it applies (< 10 x)
(droplist '(< _ 10) '(1 4 5 11 9 11 20)) returns (1 4 5 11 9 11 20) ; it applies (< x 10)
(droplist (lambda (x) (> x 10)) '(1 4 5 10 11 9 20)) returns (11 9 20)This function checks if a string ends with a specific substring:
(endwith "test" "st") ; true
(endwith "test" "at") ; nil
This function takes as input a list and returns another list, where each element is associated with its index. This function takes a second optional parameter, which is the index initial value. By default the value is 0.
(setq a '(a b c))
(loop c (enum a)
println(c)
)
; (0 a)
; (1 b)
; (2 c)
(loop c (enum a 3)
println(c)
)
; (3 a)
; (4 b)
; (5 c)comparison between two elements to verify equality
neqcorresponds to (not (eq ..))
(setq x 100)
(eq x 100) ; returns true(emptyp '()) ; trueAllows to evaluate a string as a Lisp expression or to evaluate a list.
(eval (list 'cons ''a '''(1 2 3))) ; gives (a 1 2 3)
(eval "(cons 'a '(1 2 3))") ; also gives allows to transform a string into a list of atoms.
(explode "abcd") ; yields (a b c d)Makes it possible to extract a sub-list between two indexes or a sub-string between numerical indexes or sub-strings. It is possible to give negative indexes which are then calculated from the end of the list or the string.
In the case of a string if the first index is also a string and the second index a number, then this number defines the number of characters to be extracted.
If only one argument is given, the function is equivalent to "@".
The operator "@@" is equivalent.
These two operators must be placed just before the double-quotes.
- The
+indicates that the searched string must be part of the final string. - The
-indicates that the search must be done reverse from the end of the string. - The
-+combines the two operators. The search is done reverse with it being part of the final string.
Note that "-" used at the last argument, without any value, indicates that we extract up to the end
(extract '(1 2 3 4 5) 1 3) ; gives (2 3)
(extract "12345" 1 3) ; gives "23".
(extract "abcdefghij" "b" "e") ; gives "cd".
(extract "abcdefghij" +"b" +"e") ; gives "bcde".
(extract "abcdefghij" "b" 3) ; gives "cde".
(extract "abcdefghij" +"b" 3) ; gives "bcde".
(extract "12345" -2) ; gives "4".
(extract "12345" 1 -1) ; gives "234".
(extract "/home/test/titi/toto/name.txt" -"/" -) ; yields "name.txt"
(extract "/home/test/titi/toto/name.txt" -+"/" -) ; yields "/name.txt"
; We can also use @@ in lieue of extract
(@@ "/home/test/titi/toto/name.txt" -"/" -) ; yields "name.txt"
(@@ "/home/test/titi/toto/name.txt" -+"/" -) ; yields "/name.txt"
writes a string at the end of a file
- This function is very similar to filter however, it cannot compose with other high level functions such as map, takewhile or drop.
- Second, the value from the list is always appended at the end of the condition, unless you use
_as a slot filler.
As such, it is not expanded into a loop instruction as filter and is much faster.
(filterlist '(< 10) '(1 4 5 10 11 20)) returns (11 20), we test (< 10 list_value)
(filterlist '(< _ 10) '(1 4 5 10 11 20)) returns (1 4 5), we test (< list_value 10)
; Note that (filter '(< 10) '(1 4 5 10 11 20)) returns (1 4 5)
(filterlist (lambda (x) (< x 10)) '(1 4 5 10 11 20)) returns (1 4 5)Note that: (filterlist '(< 10) '(1 4 5 10 11 20)) is equivalent to (filterlist '(< 10 _) '(1 4 5 10 11 20)).
returns the position of e in o or nil. o is either a list or a string.
(find "abcdef" "bc") ; gives 1
(find "abcdef" "bd") ; gives nilreturns a list of all positions of the sub-string in the string.
(findall "abcdefabdefabghabtr" "ab") ; gives (0 6 11 15)Flatten a list or a dictionary.
(flatten '( ( (1 2) (3 4)) (5 6))) ; yields (1 2 3 4 5 6) converts a string into a float (32 bits)
(float "12.3") ; gives 12.3Converts a list into a list of floats. e can also be more than one elements.
(floats '(1.2 3.3 4 5))
(floats 1.2 3.3 4 5) ; is also acceptableflips the two first arguments of a function.
Note: If you use flip on a dictionary, it will reverse keys and values.
(flip (- 10 2)) ; yields: -8Open a text file with its pathname:
op is:
- 'r': read mode
- 'w': write mode
- 'a': append mode
(setq fe (fopen "/home/user/toto" "r")It returns a specific object of type file_element_, which can be used with other methods.
(setq fe (fopen "/home/user/toto" "r")
(fclose fe)Close a file_element_ object.
Reads nb bytes from the current file_element_ object.
(setq fe (fopen "/home/user/toto" "r")
(fgetchars fe 100)
Write str at the current position in the file_element_ object.
(setq fe (fopen "/home/user/toto" "r")
(fputchars fe "test")Return the size of the file either through its pathname or a file_element_ object.
(setq fe (fopen "/home/user/toto" "r")
(fsize fe)Position the reading head within the file_element_ object at pos.
(setq fe (fopen "/home/user/toto" "r")
(fseek fe 100)Return the position of the current head position in the file_element_ object.
(setq fe (fopen "/home/user/toto" "r")
(ftell fe)writes a string to a file
reads a text file (UTF8) and returns the content as a string of bytes: (fread "file")
writes a string to a file
A heap is a structure in which element are automatically sorted out according to the comparison provided. The heap is implemented with a binary tree, where elements are compared through the comparison operator or lambda.
-
A heap can be created with a first list of values.
-
An element is inserted in a heap with: insert.
-
An element is removed from a heap with: pop, popfirst, poplast.
-
car returns the first element of the structure
-
cdr does not apply in this context.
-
@ works, the index is used to traverse the structure in a prefix way (top-down).
-
If comparison is nil or (), then the default comparator is:
>=<. Note that(>=< x y)returns:
- -1 if x is lower than y
- 0 if x is equal to y
- 1 if x is greater than y
- If comparison is a lambda expression, then it must return
- -1 if x is lower than y
- 0 if x is equal to y
- 1 if x is greater than y
(setq h (heap '>=< 10 30 20 19 12)) ; h is (10 12 19 20 30)
(insert h 2) ; h is (2 10 12 19 20 30)
(pop h 19) ; h is (2 10 12 20 30)
; We sort out elements according to their first element
(setq comparison (\(x y) (>=< (car x) (car y))))
(setq h (heap comparison '(16 (0 3)) '(11 (0 2)) '(11 (1 1)) '(18 (2 0))))
; h is now ((11 (0 2)) (11 (1 1)) (16 (0 3)) (18 (2 0)))
(car h) ; is (11 (0 2))
(@ h 0) ; is (16 (0 3)), which is the root of the tree
(@ h 1) ; is ((11 (0 2)) (11 (1 1))) since they share the same first element
(@ h 2) ; is (18 (2 0))
(@ h -1) ; is (18 (2 0)), the last node of the tree
; You can loop on values
(loop c h
(print c)
)
(to_list h) ; is ((11 (0 2)) (11 (1 1)) (16 (0 3)) (18 (2 0)))
; Note that the node that contains two values has been reverted compared to to_list
(to_llist h) ; is ((11 (1 1)) (11 (0 2)) (16 (0 3)) (18 (2 0)))
test the predicate, if it's true execute THEN if not ELSE. ELSE is optional.
(if (eq x 10) (println true) (println false))test the predicate, if it's true execute THEN if not ELSE. The ELSE is actually a block of instructions.
; if x ≠ 10 then (setq x 20) and (println false) will be executed
; otherwise only (println true)
(ife (eq x 10) (println true) (setq x 20) (println false))This method returns the imaginary part of a complex number.
(setq c 12,-3i)
(set r (imaginary c)) ; r is -3returns true or nil if e in o. o is either a list or a string.
(in "abcdef" "bc") ; gives true
(in "abcdef" "bd") ; gives nilAllows to read an input from keyboard.
You can also provide a string that can be modified in input
; keyboard reading of a string
(setq v (input))
; We can also modify the content of v again
(setq v (input v))converts a string into an integer value
(integer "12") ; gives 12converts a list into a list of integers. e can also be more than one elements.
(integers '(1 3 4 5))
(integers 1 3 4 5) ; is also acceptableInserts the e element in l at the idx position.
l can be a list or a string
(insert '(1 2 3) 4 1) ; gives (1 4 2 3)There is a second use of insert with a function. In this case, the function is used to determine where to add the element.
IMPORTANT: insert uses a dichotomy algorithm to store elements in a list. However, if you have a large number of elements, it is much more efficient to use a heap
(setq r '(10 20 30 40 50))
(insert r 15 '<) ; yields (10 15 20 30 40 50)
(insert r 35 '<) ; yields (10 15 20 30 35 40 50)transforms a list of atoms into a string
(join '(a b c) '/) ; gives "a/b/c".
Four actions:
-
(key): creates a dictionary -
(key k v k' v' k" v"...): Creates a dictionary with key/value couples -
(key d k v k' v' k" v"...): sets key/value couples in dictionary d -
(key d k): returns the value in the dictionary d for key k
Note: However, key can create a dictionary indexed on strings, it is better to use dictionary for this purpose.
; We create a dictionary
(setq d (key))
; Values are added to the dictionary
(key d "a" "e" "b" "c" "d" "e")
; We display the value for the key "a".
(println (key d "a"))-
(keyi): creates a dictionary -
(keyi k v k' v' k" v"...): Creates a dictionary with key/value couples -
(keyi d k v k' v' k" v"...): sets key/value couples in dictionary d -
(keyi d k): returns the value in the dictionary d for key k
Note: However, keyi can create a dictionary indexed on integers, it is better to use dictionaryi for this purpose.
; We create a dictionary
(setq d (keyi))
; We add a value in the dictionary
(keyi d 12 "e" 17 "b" 15 "hh")
; The value for key 12 is displayed.
(println (keyi d 12))-
(keyn): creates a dictionary -
(keyn k v k' v' k" v"...): Creates a dictionary with key/value couples -
(keyn d k v k' v' k" v"...): sets key/value couples in dictionary d -
(keyn d k): returns the value in the dictionary d for key k
Note: However, keyn can create a dictionary indexed on numbers, it is better to use dictionaryn for this purpose.
; We create a dictionary
(setq d (keyn))
; We add a value in the dictionary
(keyn d 12 "e" 17 "b" 15 "hh")
; The value for key 12 is displayed.
(println (keyn d 12))Returns the keys of a container
(print (keys@ d)) Saves the argument under the provided label
(label myLabel (lambda (x) (eq x 10))Note that we accept \ and λ (Unicode 955) as substitute characters for the keyword lambda
( (lambda (x y) (+ x y)) 10 20)
( (\ (x y) (+ x y)) 10 20)
( (λ (x y) (+ x y)) 10 20)
returns the last element of a list or the last character of a string.
(last '(1 2 3)) ; returns 3
let is a combination of setq and block. It allows you to create local variables, which only exists within the confines of this instruction. When the let is terminated, these variables are removed from the stack.
(setq r 1000)
(let ((r 22)
(v 10))
(if (< r v)
(+= r 1)
(+= r 20))
r) ; returns 42
(println r) ; however when back r is still 1000
Create a string that shares the same id as a given atom. This is especially useful to modify the behaviour of the tokeniser in LispE.
(see cosine for an example)
; "BEGIN" and "END" have now the same ids as '( and ')
(link "BEGIN" (atom "("))
(link "END" (atom ")"))
; It is now possible to evaluate as if it was: (+ 10 20)
BEGIN + 10 20 END
; we replace the + sign with the *
(link "+" '*)
(+ 10 20) ; is now 200
creates a list from the arguments
(list 'a 12 34) ; gives (a 12 34)Creates a linked list from the arguments.
A linked list is a list where each element is linked to the next through a pointer.
A linked list can contain cycles.
- push and pop push and remove an element at the beginning of a linked list by default.
- cdr can indefinitely loop if the list contains a cycle.
- loop will detect any cycle and will stop once all elements have been visited.
; or a list of elements as for a regular list operation
(setq ll (llist 10 20 30))
(push ll 100) ; yields (100 10 20 30)
(extend ll ll) ; connects then end of the list with its beginning creating a cycle
; The following code will loop 6 times in this 4 elements cyclic list
(loopcount 6
(setq ll (cdr ll))
(println ll)
)
; To create a linked list out of a list
(setq lbis (to_llist (list 20 30 40 50)))
; the ... indicates that the list contains a cycle
(10 20 30 100 ...)
(20 30 100 10 ...)
(30 100 10 20 ...)
(100 10 20 30 ...)
(10 20 30 100 ...)
(20 30 100 10 ...)loads and runs a LispE program provided as a file.
(setq tst (load "file.lisp"))To avoid some name conflicts, it is possible to load a file within a namespace. Functions then will be accessed with the space operator.
Note: namespace in this case is an atom.
(load "file.lisp" truc)Same as load, but takes a string as input.
This instruction protects a block of instructions in a thread. key is a string that is used to identify the lock. It is implemented as a recursive mutex.
allows to iterate on a list or a string: (loop var list instruction). The last element of the iteration returns the final result.
(loop i '(1 2 3)
(print i)
(+ i 2)
)lloop is used to iterate in parallel among different lists.
To iterate on different types, such as dictionaries, use: mloop.
In that case, you need to provide as first argument, a list of variables and next to it a succession of lists, whose number must match the number of variables.
; x will loop on (1 3 4)
; y will loop on (5 6 7)
; z will loop on (9 10 13)
(lloop (x y z) '(1 3 4) '(5 6 7) '(9 10 13) (println (+ x y z)))
; 15
; 19
; 24allows to iterate nb times. The last element of the iteration returns the final result.
(setq i 0)
(loopcount 10
(print i)
(+= i 2)
)The mask instruction works as a collection of if/then/else values, which are collected as a list of Boolean values:
If the last part of the expression is missing, then the default value is nil.
(setq s "abcdefghi")
(setq v (mapcar 'vowelp s)) ; v is (1 0 0 0 1 0 0 0 1)
(mapcar 'upper (filtercar 'vowelp s)) ; is ("A" "E" "I")
(filtercar 'consonantp s) ; is ("b" "c" "d" "f" "g" "h")
; each vowel is then replaced with its uppercase
(mask '(1 0 0 0 1 0 0 0 1) (mapcar 'upper (filtercar 'vowelp s)) (filtercar 'consonantp s))
; ---> ("A" "b" "c" "d" "E" "f" "g" "h" "I")
This instruction is similar to map. It offers a much faster implementation. However, it cannot compose with other high level functions such as filter or takewhile. Furthermore, it can only apply functions of arity 1.
(maplist (lambda(x) (+ x x)) (iota 10)) ; (2 4 6 8 10 12 14 16 18 20)By default, maplist utilises the first element produced by the lambda to define the type of list that will be built. For instance, if this element is a string, maplist will create a strings object.
maplist can take a fourth parameter, which when false forces the output to be a regular list.
(type (maplist (lambda(x) (+ x x)) (iota 10))) ; yields integers_
(type (maplist (lambda(x) (+ x x)) (iota 10) false)) ; yields list_Furthermore, you can use maplist with a simple list containing an operator with values. You use then _ as a slot filler.
(maplist (- 10 _) (iota 10)) ; (9 8 7 6 5 4 3 2 1 0)
(maplist (- _ 10) (iota 10)) ; (-9 -8 -7 -6 -5 -4 -3 -2 -1 0)
Note that: (maplist (- 10 _) (iota 10)) is equivalent to (maplist (- 10) (iota 10)).
mapcar shares the same implementation as maplist, however it systematically returns a regular list.
This function has been implemented to keep some consistency with other Lisp implementations.
(mapcar (\(x) (+ x 1)) (integers 1 2 3)) ; is equivalent to
(maplist (\(x) (+ x 1)) (integers 1 2 3) false)This instruction is used with lists to handle potential list infinite loops. It has two different utilisations:
-
(mark l B): marks the list with the Boolean value: B -
(mark l): returns the Boolean value attached to this list...
Note that in the case of an infinite loop, the list is displayed with: '...' instead of the element that is infinitely repeated:
(setq a '(1 2 3))
(setq b '(10 20 30))
; we create an infinite loop
(push a b)
(push b a)
(println a) ; display: (1 2 3 (10 20 30 ...))
(println b) ; display: (10 20 30 (1 2 3 ...))
; Looping in the structure
; when mark is true, we stop ans display a warning message
(defun traverse (l)
(check (consp l)
(ife (mark l)
(println "Warning: infinite loop")
(println (at l 0))
(mark l true)
(traverse (car l))
(traverse (cdr l))
(mark l false)
)
)
)
(traverse a)
This instruction checks whether a value returned by catch was an error or detects errors in a sequence of instructions.
maybe exposes two different modes:
- It has one single argument, then it returns true if the value is a maybe object returned by a catch.
- It has at least two arguments. Each instruction is executed in sequence except for the last one. If one instruction fails, then the last one is executed.
(setq c
(catch
(cons ' a)
)
)
; With one parameter, we can then use the caught value to display an error message
(if
(maybe c)
(print Error: c)
(print No error)
)
; with more than one parameters
; if an error occurs in one of the instructions, then the last instruction is executed...
(maybe (cons 'a ())
(cons 'b ())
(cons 'c)
(println "An error occurred")
)
Returns the largest element in a string of arguments or the largest element in a list.
(max 1 4 5 10 8) ; returns 10
(max '(1 4 5 10 8)) ; returns 10Returns the smallest element in a string of arguments or the smallest element in a list
(min 1 4 5 10 8) ; returns 1
(min '(1 4 5 10 8)) ; returns 1Returns a list containing the largest and the smallest element in a list
(minmax 1 4 5 10 8) ; returns (1 10)mloop is used to iterate in parallel among different containers that are not all lists.
In that case, you need to provide as first argument, a list of variables and next to it a succession of lists, whose number must match the number of variables.
; x will loop on (1 3 4)
; y will loop on {"a":10 "b":20 "c":4} (actually on the values not the keys)
; z will loop on (9 10 13)
(mloop (x y z) '(1 3 4) {"a":10 "b":20 "c":4} '(9 10 13) (print (+ x y z)))
; 14
; 33
; 27If CONDITION is true, execute the list of instructions: I1,I2... to In.
If CONDITION is nil, execute ELSE_I.
(setq k 10)
; if k < 100, we increment it
(ncheck (< k 100)
(println 'end) ; if k == 100, we stop and display a message
(println k)
(+= k 1)
)
List concatenation. All arguments should be a list except for the last one. The concatenation is made into the first argument...
(nconc) is nil
(setq x '(a b c)) => (a b c)
(setq y '(d e f)) => (d e f)
(nconc x y) => (a b c d e f)
; x is now (A B C D E F)
List concatenation. All arguments should be a list except for the last one. The concatenation creates a new list... nconcn is identical to nconc except for the fact that it creates a new list.
(nconcn) is nil
(setq x '(a b c)) => (a b c)
(setq y '(d e f)) => (d e f)
(nconcn x y) => (a b c d e f)
; x is not modified
Boolean Negation: (not true) gives false
converts a string into a number
(number "12") ; gives 12Returns the value corresponding to a sequence of keys.
The container can be a list, a matrix, a tensor or a dictionary.
Other name to at.
(setq r (rho 2 2 (iota 5))) ; r = ((1 2) (3 4))
(println (nth r 0 1)) ; is 2converts a list into a list of numbers. e can also be more than one elements.
(numbers '(1.2 3.3 4 5))
(numbers 1.2 3.3 4 5) ; is also acceptable(or (eq 10 20) (eq 20 20)) ; returns trueover applies a function or a lambda to list, and replaces the value of list with the new values.
(setq l '(1 2 3))
(over 'rotate l) ; l is now (3 1 2)Read the pipe on the command line...
Return nil when the pipe is empty...
; As long as there is data in the pipe, we read it...
(setq p (pipe))
(while p (setq p (pipe))
Removes a value from a list, a dictionary or a string.
(pop '(A b c) 1) ; gives (A c)
(pop {12:34} 12) ; gives {}.
(pop "abc" 2) ; gives "ab". Removes the first value from a list or a string.
(popfirst '(A b c)) ; gives (b c)
(popfirst "abc") ; gives "ab". Removes the last value from a list or a string.
(poplast '(A b c) 1) ; gives (A b)
(poplast "abc" 2) ; gives "ab". Displays in a more readable form a parenthesized structure. The last parameter mx is optional. It defines the longest string that can be produced on a line by concatenating different sub-lists.
Displays the values on the screen
Displays the values on the screen by separating them with a space and placing a carriage return at the end.
Displays the values on the screen on stderr.
Displays the values on the screen by separating them with a space and placing a carriage return at the end, on stderr.
adds an item to the l list. Be careful, if the list is a constant element, this operation returns a copy.
(push '(1 2 3) 4) ; returns (1 2 3 4) which is a copy of the initial list.
; So, pay attention to the following code:
(push '(1 2 3) 12) ; returns a copy of the listadds an item at the beginning of the l list. Be careful, if the list is a constant element, this operation returns a copy.
(pushfirst '(1 2 3) 4) ; returns (4 1 2 3) which is a copy of the initial list.
; So, pay attention to the following code:
(pushfirst '(1 2 3) 12) ; returns a copy of the listadds an item at the end of the l list. Be careful, if the list is a constant element, this operation returns a copy.
(pushlast '(1 2 3) 4) ; returns (1 2 3 4) which is a copy of the initial list.
; So, pay attention to the following code:
(pushlast '(1 2 3) 12) ; returns a copy of the listadds an item to the l list, if this value is not nil. Be careful, if the list is a constant element, this operation returns a copy.
(pushtrue r 4 (<1 9) (< 3 1)) ; returns (4 true) (< 3 1) is skipped
; pushtrue can be combined with andvalue
(setq l ())
(loop r (irange 0 10 1)
(pushtrue l
(andvalue
(eq (% r 2) 0)
(* 2 r)
)
)
)
; The result is then: (0 4 8 12 16)
This is equivalent to:
(loop r (irange 0 10 1)
(if (eq (% r 2) 0)
(push l (* 2 r)
)
)The operator associated with '. Returns without evaluating its argument.
Returns a list of values starting at initial, ending at limit in steps.
These lists are either a numbers type or an integers type according to the different values given as arguments
(range 1 10 1) ; yieds (1 2 3 4 5 6 7 8 9), which is an 'integers' typeReturns a list of values starting at initial, ending at limit in steps.
The difference with range is that the limit is part of the values.
These lists are either a numbers type or an integers type according to the different values given as arguments
(rangein 1 10 1) ; yieds (1 2 3 4 5 6 7 8 9 10), which is an 'integers' typeExits a loop or a function and returns its argument.
Replaces all the occurrences of search in object with replace. Returns the number of replacements.
object can be any container or a string.
(setq l (integers 10 20 10 40))
(setq nb (replaceall l 10 100)) ; nb is 2 and l is now: (100 20 100 40)This method returns the real part of a complex number.
(setq c 12,3i)
(set r (real c)) ; r is 12Resets the marks on lists for control over infinite loops.
- l is a list, a matrix or a tensor
- nb:
- nb < 0: the container is rotated to the right of nb increments
- nb > 0: the container is rotated to the left of nb increments
- false or absent: the container is rotated to the right of 1 increment
- true: the container is rotated to the left of 1 increment
- line:
- false or absent: if the container is a matrix or a tensor, the matrix is rotated along the columns
- true: if the container is a matrix or a tensor, the matrix is rotated along the lines
(rotate "abcde") ; yields "eabcd"
(rotate "abcde" true) ; yields "bcdea"
(⌽ (iota 10)) ; yields (2 3 4 5 6 7 8 9 10 1)
(⌽ (iota 10) true) ; yields (10 1 2 3 4 5 6 7 8 9)
(iota 10) ; (1 2 3 4 5 6 7 8 9 10)
(rotate (iota 10) -2) ; (9 10 1 2 3 4 5 6 7 8)
(rotate (iota 10) 2) ; (3 4 5 6 7 8 9 10 1 2)Exit a function and return a value
(function call(i)
(while (< i 10)
(if (eq i 5)
(return i)
(-= i 1)
)
)
)
Reverse a string or a list.
local can be either:
- false: in this case the list is reversed locally (the default value).
- true: in this case, a duplicate of the list is returned
(reverse '(a b c)) ; gives (c b a)
(reverse "abc") ; gives "cba".
(setq l (iota 10)) ; l is (1 2 3 4 5 6 7 8 9 10)
(reverse l true) ; l is now (10 9 8 7 6 5 4 3 2 1)Search for a sub-string of characters from the end.
Applies action to each element of lst and returns the first value that is not null.
(scanlist (\(x) (if (> x 5) (* 2 x))) (range 1 10 1)) ; returns 12 (2 x 6)Returns the first non nil value.
; returns either a value in the dico if the key is present of the key itself
(select (key dico k) k)
Allows to make a recursive call in a function or lambda.
( lambda (x) (if (eq x 1) 1 (+ x (self (- x 1))))) 12))
Creates sets of elements.
sets, setn, seti create respectivement:
- sets: set of strings
- seti: set of integers
- setn: set of numbers
set is used to create sets of objects.
An element is pushed into a set with either insert or push.
An element is removed from a set with pop.
- You can check if an element belong to a set with in.
- You can access an element in a set with @.
- You can loop on all values in a set.
(setq strset (sets "ab" "cd" "ef"))
(push strset "ok")
(if (in s "ok") 'ok 'no)
(setq o_set (set '(1 2 3) '(1 2) '(8 9))
(println (type (@ o_set '(1 2))) ; list_
Set a value at the position corresponding to the sequence of keys
(setq r (rho 2 2 (iota 5))) ; r = ((1 2) (3 4))
(set@ r 0 1 100)) ; r is now ((1 100) (3 4))Replaces a range of values between beg and end with value.
set@@ is a synonym to setrange.
(setq r '(1 2 3 4 5 6))
(set@@ r 0 3 100) ; r is now (100 4 5 6)Replace a value or a sequence of values corresponding to a sequence of keys, according to a shape. The container should be a flat list of values. shape should be a list of values that provides the virtual dimensions that are projected onto the flat list of values. This is the pendant of atshape.
set@@@ is a synonym to setshape.
Initialization of a global variable with a value. If label is a function, then it replaces the function body with value.
Initialization of a variable with a value
Replace a value or a sequence of values corresponding to a sequence of keys, according to a shape. The container should be a flat list of values. shape should be a list of values that provides the virtual dimensions that are projected onto the flat list of values. This is the pendant of atshape.
keys cannot be negative.
setshape is the official name for the operator set@@@
(setq fv (range 0 60 1))
(setq sh (integers 3 4 5))
; changing one value
(set@@@ fv sh 1 2 3 100)
;changing a sequence of values
(set@@@ fv sh 1 2 '(-1 -2 -3 -4 -5))
seth can only be used in conjunction with threadspace. It creates a variable in the common thread space.
The access to this variable is automatically protected with an internal lock. Note that this lock is the same as in threadstore, threadretrieve and threadclear. Once a variable has been created with seth, it can only been accessed within threadspace. However, it is then treated as a regular variable as shown below.
; We create in the main section two specific thread safe variables titi and toto
(threadspace
(seth titi 10)
(seth toto (rho 4 4 '(0)))
)
; titi and toto are accessed via threadspace in this thread
(dethread tst(x y)
(threadspace
(+= titi x)
(set@ toto 0 y titi)
)
)
; We call our threads
(tst 10 0)
(tst 20 1)
(tst 30 2)
(tst 40 3)
; we wait for their completion
(wait)
; again titi and toto are only available in threadspace
; Note that threadspace is equivalent to space thread...
(space thread
(println titi)
(println toto)
)
Replaces a range of values between beg and end with value.
This method utilizes the same interval description as extract.
setrange can also be written: set@@
(setq r '(1 2 3 4 5 6))
(setrange r 0 3 100) ; r is now (100 4 5 6)converts a string into a short (16 bits)
(short "12") ; gives 123Converts a list into a list of shorts. e can also be more than one elements.
(shorts '(12 33 4 5))
(shorts 12 33 4 5) ; is also acceptableChanges the sign of e.
(sign 10) ; -10
(sign -10) ; 10- If e is negative: returns -1
- If e is 0: returns 0
- If e is positive: returns 1
Returns the size of a list or a string
Put a thread in sleep mode for tm milliseconds.
This instruction slices a list or a string into a list of slices of same size.
(slice '(a b c d e f g h i j k l) 3) ; ((a b c) (d e f) (g h i) (j k l))Sort a list. Important, the comparator must not return true in case of a tie. Thus <= is a bad comparison operator.
(sort '< '(1 7 9 4 3)) (1 3 4 7 9)
(sort '> '(1 7 9 4 3)) (9 7 4 3 1)The space operator makes it possible to execute functions that were defined in a namespace with defspace or load or use.
This operator works as a block.
The main namespace is called: mainspace_.
It is possible to embed different space calls within a space.
Note: space thread is actually equivalent to threadspace.
; We define some functions in a space named truc
(defspace truc
(defun calculus (x y)
(+ x y)
)
(defun toto (u v)
(* u v)
)
)
(defun calculus (x y)
(+ x (* x y))
)
(space truc
(setq r (calculus 10 20))
(setq v (toto 100 200))
; here we force the call to the global implementation of calculus within another space definition
(setq x (space mainspace_ (calculus 10 5)))
)
(setq o (calculus 10 20)) ; Note that in this case we call the local version of calculusThis function checks if a string starts with a specific substring:
(startwith "test" "te") ; true
(startwith "test" "at") ; nil
Converts its argument into a string
Converts its argument into a string of bytes.
A string byte can also be created with the b"" notation:
(setq s b"This is a string byte")Converts its argument (a number) into a string with a format based on C function printf.
(stringf 123 "0x%X") ; is 0x7BCheck if e is a string
converts a list into a list of strings. e can also be more than one elements.
(strings '("a" "b" "c" "d"))
(strings "a" "b" "c" "d") ; is also acceptableconverts a list into a list of byte strings. e can also be more than one elements.
(stringbytes '("a" "b" "c" "d"))
(stringbytes "a" "b" "c" "d") ; is also acceptable- c0...cn are either strings or numbers.
- codes is a block of code
This method works as a switch in C++ or Java. It checks v against the different case values in the structure.
However, switch uses an internal dictionary, which makes this comparison straightforward.
The default value is implemented as in cond, with true.
(setq c 10)
(switch c
(0 1)
(10 'yes)
(true 'unknown)
) ; yields yes- This function is very similar to takewhile however, it cannot compose with other high level functions such as map, takewhile or drop.
- Second, the value from the list is always appended at the end of the condition, unless you use
_as a slot filler..
As such, it is not expanded into a loop instruction as takewhile and is much faster. takelist extracts elements from a list that comply with the condition. It stops when an element does not comply anymore.
(takelist '(> 10) '(1 4 5 10 9 11 20)) returns (1 4 5) ; it applies (> 10 x)
(takelist '(> _ 1) '(4 5 1 10 9 11 20)) returns (4 5) ; it applies (> x 1)
(takelist (lambda (x) (< x 10)) '(1 4 5 10 11 20)) returns (1 4 5)Extracts nb elements from the beginning of lst. If beginning is false, then extracts the last nb values from lst.
Note that if nb is negative and beginning is true, then the elements are also extracted at the end.
(takenb 3 '(1 2 3 4 5)) ; (1 2 3)
(takenb 3 '(1 2 3 4 5) false) ; (3 4 5)
(takenb -3 '(1 2 3 4 5)) ; (3 4 5)tally returns the number of elements of a matrix or a tensor. Applied to a list, it simply returns its size.
(setq r (rho 3 4 5 (iota 60)))
(tally r) ; 60This instruction transforms any kind of container into a list.
(to_list (numbers 10 20 30)) ; is now a listThese is a second implementation of this method with three parameters.
In this case, LispE creates a list of nb values.
(to_list "a" 10) ; ("a" "a" "a" "a" "a" "a" "a" "a" "a" "a")This instruction transforms any kind of container into a llist (linked list).
(to_llist (list 10 20 30)) ; is now a llistThis function transforms a list of values into value lists, matrices or tensors.
A list can be transformed into these elements only they present a regularity in types and sizes.
(setq l '((1 2 3) (4 5 6)))
(to_tensor l) ; a matrix_integer
(setq l '((1 2 3) (4 5 6 8)))
(to_tensor l) ; returns a list, the sublists have different sizesThis instruction returns the data that were stored in the protected list with threadstore, within a thread. namespace is a string that defines a namespace in which your data is stored. You can implement as many namespaces as you want.
If you use threadretrieve without any namespace, it returns a dictionary containing all the namespaces and their values.
(dethread call(i)
(setq l (range 1 i 1))
; our namespace is "here":
(threadstore "here" l)
)
(call 10)
(call 100)
(call 20)
(wait)
(println (threadretrieve "here"))
This instruction should be used in a thread to store elements that should survive the thread itself. This instruction stores the information in a protected list that can be accessed through retrieve. namespace is a string that defines a namespace in which your data is stored. You can implement as many namespaces as you want.
(dethread call(i)
(setq l (range 1 i 1))
(threadstore "other" l)
)Clear the protected list used in threads to keep data alive. namespace is a string that defines a namespace in which your data is stored. You can implement as many namespaces as you want.
If you do not provide any namespace, then all spaces will be deleted.
(dethread call(i)
(setq l (range 1 i 1))
(threadstore "tobecleared" l)
)
(call 10)
(call 100)
(call 20)
(wait)
(println (threadretrieve "tobecleared"))
; we clear the namespace: "tobecleared"
(threadclear "tobecleared")threadspace works as a block in which thread safe variables can be created and manipulated. Variables in threadspace are created with seth. However their access is similar to any variables henceforth.
Note: threadspace is actually equivalent to space thread.
; We create in the main section two specific thread safe variables titi and toto
(threadspace
(seth titi 10)
(seth toto (rho 4 4 '(0)))
)
; titi and toto are accessed via threadspace in this thread
(dethread tst(x y)
(threadspace
(+= titi x)
(set@ toto 0 y titi)
)
)
; We call our threads
(tst 10 0)
(tst 20 1)
(tst 30 2)
(tst 40 3)
; we wait for their completion
(wait)
; again titi and toto are only available in threadspace
; Note that threadspace is equivalent to space thread...
(space thread
(println titi)
(println toto)
)
Activates the trace during execution: (trace true)
Returns the type of its argument
Remove the duplicates in lst. The comparison is done with: ==
Loads a dynamic library whose path is given by the environment variable: LISPEPATH.
It is also possible to load this library within a namespace.
Use space to access the different functions.
This function returns an UUID in agreement with UUID RFC 4122, version 4 (fully random). It returns a string value containing hexadecimal values of the form: XXXXXXXX- 4XXX- 1XXX- XXXX- XXXX
(setq u (uuid)) ; u is 80c67c4d-4c4d-14cd-e58d-eb3364cdWake up all threads waiting on key.
Returns values from a dictionary (see keys@)
This instruction allows you to wait for all threads to finish. See dethread for an example.
Put a thread on hold until it is woken up with trigger on that key.
Allows looping as long as a condition is true.
(setq v 10)
(while (> v 0) (setq v (- v 1))Allows looping in a list with var as long as a condition is true.
(setq v (iota 10))
(whilein x v (< x 10) (print x))