INTRODUCTION

This manual page documents the standard library of variables and functions available for use in KL-EL expressions. For documentation on how to embed the KL-EL compiler and interpreter in an application, see klelapi(3). For a tutorial on how to use the library, see kleltut(3). For documentation on the expression language itself, see klellang(3).

FUNCTIONS

The following sub-sections describe the various arithmetic, string, and time functions exported by the standard library for general use in KL-EL expressions.

ARITHMETIC FUNCTIONS

int abs(int x);: Returns the absolute value of x.
int entier(real x);: Converts x to an integer, rounding towards negative infinity.
real real(int x);: Converts x to a real number.
int max(int x, int y);: Returns the larger of x and y.
int min(int x, int y);: Returns the smaller of x and y.
bool odd(int x);: Returns true if x is odd.

STRING FUNCTIONS

int cksum(string x);: Computes a simple 16-bit checksum of x using the original BSD checksum algorithm.
string chr(int x);: Returns a string containing a single character whose character code is equal to x.
int ord(string x);: Returns the character code of the first character of x.
int strlen(string x);: Returns the length in bytes of x.
string string_of_bool(bool x);: Returns the string "true" if x is true; otherwise, it returns "false".
string string_of_real(real x);: Returns the string representation of x in decimal notation.
string string_of_int(int x);: Returns the string representation of x in decimal notation.
string dec_of_int(int x);: An alias for string_of_int.
string hex_of_int(int x);: Returns the string representation of x in hexadecimal notation.
string oct_of_int(int x);: Returns the string representation of x in octal notation.

TIME FUNCTIONS

int now();: Returns the number of seconds since the epoch.
string ctime();: Returns the current time as reported by the ctime(3) function.

ERROR FUNCTIONS

int abort_bool(string message);: Aborts execution (produces a runtime error, causing KlelExecute to return NULL) with the given message pushed onto the error stack. Does not return, but purports to return a boolean, allowing it to be used in boolean expressions.
int abort_int(string message);: As for abort_bool, but purports to return an integer.
int abort_real(string message);: As for abort_bool, but purports to return an real number.
int abort_string(string message);: As for abort_bool, but purports to return an string.

VARIABLES

The following variables are defined in the standard library:

                      ======= DEFINITION =======
                              t  d
                              y  e
                              p  s
                              e  c
                                 r
                                 i
                                 p
                                 t
                                 i
                                 o
                                 n
   ======   VARIABLE  ==========================
   true                       B  Boolean true
   false                      B  Boolean false
   pi                         R  3.1415926535897932384 (approximation)
   e                          R  2.7182818284590452354 (approximation)