Input

Input

Primarily, input from the keyboard is done using "read" and "line" commands.

Read

Reads data from keyboard:

: (setq aq (read))
hello
-> hello
: aq
-> hello
: print aq
-> hello
: (print aq)
hello-> hello

Line.

Reads data from keyboard and return them as a list:

: (setq aq0 (line))
hello world
-> ("h" "e" "l" "l" "o" " " "w" "o" "r" "l" "d")
: (print aq0)
("h" "e" "l" "l" "o" " " "w" "o" "r" "l" "d")-> ("h" "e" "l" "l" "o" " " "w" "o" "r" "l" "d")

If we want to return it as a whole line we use (line T) instead of (line) :

: (setq aq0 (line T))
hello world
-> "hello world"
: (print aq0)     
"hello world"-> "hello world"

PicoLisp Functions Used On This Page.

The description of the picolisp functions used taken from official PicoLisp documentation (https://software-lab.de/doc/index.html) follows: 

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(read ['sym1 ['sym2]]) -> any

Reads one item from the current input channel. NIL is returned upon end of file. When called without arguments, an arbitrary Lisp expression is read. Otherwise, a token (a number, an internal symbol, a transient symbol (for punctuation), or a list of symbols (for a string)) is read. In that case, sym1 specifies which set of characters to accept for continuous symbol names (in addition to the standard alphanumerical characters), and sym2 an optional comment character. See also any, str, line, skip and eof.

: (list (read) (read) (read))    # Read three things from console
123                              # a number
abcd                             # a symbol
(def                             # and a list
ghi
jkl
)
-> (123 abcd (def ghi jkl))
: (make (while (read "_" "#") (link @)))
abc = def_ghi("xyz"+-123) # Comment
NIL
-> (abc "=" def_ghi "(" ("x" "y" "z") "+" "-" 123 ")")

(line 'flg ['cnt ..]) -> lst|sym

Reads a line of characters from the current input channel. End of line is recognized as linefeed (hex "0A"), carriage return (hex "0D"), or the combination of both. (Note that a single carriage return may not work on network connections, because the character look-ahead to distinguish from return+linefeed can block the connection.) If flg is NIL, a list of single-character transient symbols is returned. When cnt arguments are given, subsequent characters of the input line are grouped into sublists, to allow parsing of fixed field length records. If flg is non-NIL, strings are returned instead of single-character lists. NIL is returned upon end of file. See also char, read, till and eof.

: (line)
abcdefghijkl
-> ("a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l")
: (line T)
abcdefghijkl
-> "abcdefghijkl"
: (line NIL 1 2 3)
abcdefghijkl
-> (("a") ("b" "c") ("d" "e" "f") "g" "h" "i" "j" "k" "l")
: (line T 1 2 3)
abcdefghijkl
-> ("a" "bc" "def" "g" "h" "i" "j" "k" "l")

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