Alphabetical list of predicates

symbols A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


+ addition
+ strings concatenation
- subtraction
. (point) sets and gets property, invokes method
* multiplication
/ division
** exponentiation
// integer division
= unify
?= unifyable
\= not unifyable
> bigger than
< less than
=:= equal
>= bigger or equal to
=< less or equal to
=\= not equal
>> shift all bits in right
<< shift all bits in left
/\ bitwise and function
\/ bitwise or function
\ bitwise not function
=.. makes functor and arguments as a list
! (cut) partially restricts the backtracking
:= assumes equal
; (or) executes the left goal and if fails or on Next Answer executes the right one
-> (if-then-else) if the most left goal succeeds then executes the next goal, if it fails then executes last goal.


abs returns the absolute value
add_text adds a text into edit box
animate creates an animation control
assert appends a clause to the run-time database
asserta appends a clause to the run-time database (in the beginning)
assert_in appends a clause both to the run-time database and to the source Prolog text
asserta_in appends a clause both to the run-time database and to the source (in the beginning)
arccos calculates the arccosine function
arcsin calculates the arcsine function
arctg calculates the arctangent function


beep produces a short beep
bezier_line draws a Bézier curve
bitmap creates a bitmap control
bitmap_image creates a bitmap object
brush sets the filling color
button creates a button control


call starts a goal
ceiling returns integer which is bigger than the argument
char_set gets and sets the default char set
char_set_name returns the name of the char set
charAt returns a char from its position
change_style changes the stile of a Window
check_box creates a check box control
chronometer gets time intervals in milliseconds
client_pos gets position of the window's client area
client_size gets the size of window's client area
close closes a window or a file or OLE server or a socket or MYSQL connection
color_text_back sets the text background
color_text sets the text color
const checks whether a term is a constant
convert_charset changes the char set
convert_UTF8_to_local converts from UTF-8 to 8 bit char set
copy_in_edit copies the selected text into the clipboard
cos calculates the cosine function
cosh calculates the hyperbolic cosine function
count_successes count the successes of a goal
create_directory creates a new directory.
cursor sets the cursor to one of the standard cursors
cut partially restricts the backtracking
cut_in_edit cuts the selected text


delete_file deletes a file.
draw_arc draws an arc
draw_bitmap draws a bitmap image in a window
draw_chord draws a chord
draw_pie draws a pie
draw_point draws a point or takes the color of a point


edit creates an edit control
ellipse draws an ellipse
embed_server embeds an ActiveX control
enable_window Enables/Disables a window object
equal compares strings (with case and no case)
execute starts the execution of other program (usually *.EXE)
exp calculates the exponent function


fail always fails
feof checks for a end-of-file
field returns a field from a row
fill_polygon draws a polygon
first_ASCII returns the ASCII code of the first symbol
float checks whether the argument is float or converts it to float
floor returns integer which is smaller than the argument
for doing a loop
ftruncate truncates a file
functor checks a functor's name and arity


get gets a byte or integer from a file
get_check_box_value gets the value of a checkbox
get_client gets a client socket of the remote host
get_clipboard_data gets the clipboard data
get_current_directory retrieves the current directory.
get_date gets current date
get_environment_arg returns a part of a string
get_file_pos returns the position of the file pointer
get_html_form returns a form field
get_program_argument  returns the program argument passed from the command line
get_selected_text gets the selected text from an edit box
get_selection gets the selection text into an edit box
get_text gets the text value of a control
get_time gets current time
getenv returns the environment value
group_box creates a group box control


has_to unstable assignment


icon creates an icon control
integer checks whether the argument is integer or converts it to integer
is evaluates righthandside arithmetical expression and unifies the value with the lefthandside variable (Prolog 'assignment')


kill_timer kills a timer object


list_box creates a list box control
list_length returns the length of a list
less_than compares strings (with case and no case)
line draws a line
log calculates the natural logarithm
log10 calculates the logarithm with base ten
logoff Log off as an e-mail user
logon Log on as an e-mail user


max returns the maximum
menu creates a menu item
message creates a message dialog box
message_flags gets the status of the buttons
min returns the minimum
mod modulo
modify_at modifies the fact which has this consecutive number
modify_menu modifies the menu item
move_file moves a file to a new location
mysql_connect opens a connection to MYSQL server
mysql_eof checks if the end of the result is reached
mysql_fetch_row returns the next row from the MYSQL result
mysql_free_result frees the MYSQL result
mysql_num_fields returns the number of the fields from returned MYSQL result
mysql_query executes the Query on selected database on the MYSQL server
mysql_select_db selects the database from MYSQL server
mysql_store_result stores the result from the execution of a query


nl prints a new line
not_deeper_than temporally restricts the stack size
not Prolog negation
number checks if a term is a number


of that X which satisfy Y
on_the_last_step which was the fact used in the last unification
once executes a goal, but it is not re-executable
open opens a file
op defines an operator


paint_rect gets the rectangle which needs to be repainted
parent gets the parent window handle of the argument window
paste_in_edit pastes the selected text from the clipboard
pen gets/sets the current pen
pos gets a window's position
press_button presses a button at a given position
print converts a term to a string
print_file prints formatted file
print_string prints formatted string
printq converts a term to a string (without calculating it)
put puts a byte or integer in to a file


radio_button creates a radio button control
raise_event sends information from the sever back to the client
random generates random numbers
read reads a term using a dialog box
read_new_mail reads e-mail letters
read_sock reads a string from the socket
readf reads a string from a file
readln reads a line from a file
rect draws a rectangle
rem remainder
remove_directory removes a directory.
repeat always tries next answer
replace replace one string with another
retract retracts a clause from the run-time database
retract_at retracts the fact which has this consecutive number
retract_in retracts a clause both from the run-time database and from the source
retractall retracts all occurrences of a clause from the run-time database
rgb creates a color by its RGB value (Red, Green, Blue)
round returns integer which is round the argument
round_rect draws a round rectangle


s_mail sends mail (ONLY for UNIX)
scan converts a string to a term
select_color invokes an select color dialog box
select_file invokes an open/save file dialog box
select_font invokes a Select Font dialog box
send_mail send an e-mail letter
server opens an OLE server
server2 opens an OLE server which listen for events
server_socket creates a server socket
set retracts a clause and assert another one in place of it
set_at changes the fact which has this consecutive number
set_check_box_value sets the value of a checkbox
set_clipboard_data sets the clipboard data
set_content_type sets the content type
set_cookie sets a cookie on the client's browser
set_current_directory sets the current directory.
set_file_pos sets the file pointer
set_pos sets a window's position
set_selection sets the selection text into an edit box
set_size sets a window's size
set_text sets the text value of a control
set_timer creates a timer object
shell_execute opens a file by using it extension.
sign returns the sign
sin calculates the sine function
sinh calculates the hyperbolic sine function
size gets a window's size
socket returns a client socket
split splits a string using separator character
sqrt calculates the square root
static creates a static label
str_length finds the length of the given string
string_end finds ends from the given string
string_from_ASCII makes string from ASCII number
sub_string finds substrings from the given string
system_color gets system color


terminate terminates the program and displays a message
text_out draws a rectangle with a text
tg calculates the tangent function
tgh calculates the hyperbolic tangent function
the_head_of returns the head of the clause by its consecutive number
trace switches program execution to trace mode
tree_box creates a tree box control
true always succeeds
true_value returns one or zero


update_window updates the drawings in the window
url_encode encodes into the URL format


var checks if a term is a not-instantiated variable


wait waits a time interval
window creates an overlapping window
window_brush changes the window's background color
write writes a term
writeq writes a term (without calculating it)
write_sock writes the string in the socket
writef writes the string in a file


xor bitwise xor function


yes_no opens a dialog box with a yes-no question to be answered