List Generators

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<code> <code>
 +-import(lists, [seq/2]).
 +
%%% Alphanumeric characters ([a-zA-Z0-9]). %%% Alphanumeric characters ([a-zA-Z0-9]).
alnum() -> oneof(seq($a, $z) ++ seq($A, $Z) ++ seq($0, $9)). alnum() -> oneof(seq($a, $z) ++ seq($A, $Z) ++ seq($0, $9)).

Revision as of 13:16, 9 September 2008


Authors

(This is a living page, please add your own list based generators here!)

Adam Lindberg

Non-empty list

If you want to generate lists which can never be empty, it's fairly simple to wrap the standard list() generator in QuickCheck: 

nelist(G) ->
    ?LET({E, L}, {G, list(G)},
         [E|L]).


Regexp POSIX Character Classes

Generators for all the POSIX character classes in regexp. Note: some of them do not generate printable strings in Erlang. 

-import(lists, [seq/2]).

%%% Alphanumeric characters ([a-zA-Z0-9]).
alnum() -> oneof(seq($a, $z) ++ seq($A, $Z) ++ seq($0, $9)).

%%% Alphabetic characters ([a-zA-Z]).
alpha() -> oneof(seq($a, $z) ++ seq($A, $Z)).

%%% ASCII characters ([\x00-\x7F]).
ascii() -> oneof(seq(0, 127)).

%%% Space and tab ([ \t]).
blank() -> oneof([$ , $\t]).

%%% Control characters ([\x00-\x1F\x7F]).
cntrl() -> oneof(seq(0, 31) ++ [127]).

%%% Digits ([0-9]).
digit() -> oneof(seq($0, $9)).

%%% Visible characters (i.e. anything except spaces, control
%%% characters, etc.) ([\x21-\x7E]).
graph() -> oneof(seq(33, 126)).

%%% Lowercase letters ([a-z]).
lower() -> oneof(seq($a, $z)).

%%% Visible characters and spaces (i.e. anything except control
%%% characters, etc.) ([\x20-\x7E]).
print() -> oneof(seq(32, 126)).

%%% Punctuation and symbols ([!"#$%&'()*+,\-./:;<=>?@[\\\]^_`{|}~]).
punct() -> oneof("!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}\~").

%%% All whitespace characters, including line breaks ([ \t\r\n\v\f]).
space() -> oneof([$ , $\t, $\r, $\n, $\v, $\f]).

%%% Uppercase letters ([A-Z]).
upper() -> oneof(seq($A, $Z)).

%%% Word characters (letters, numbers and underscores) ([A-Za-z0-9_]).
word() ->  oneof(seq($a, $z) ++ seq($A, $Z) ++ seq($0, $9) ++ "_").

%%% Hexadecimal digits ([A-Fa-f0-9]).
xdigit() -> oneof(seq($A, $F) ++ seq($a, $f) ++ seq($0, $9)).
Retrieved from "http://www.trapexit.org/List_Generators"
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