Synopsis
Guess the data type that a string represents.
Usage
DataType_Type _slang_guess_type (String_Type s)
Description
This function tries to determine whether its argument
s represents
an integer or a floating point number. If it appears to be neither,
then a string is assumed. It returns one of three values depending on
the format of the string
s :
Integer_Type : If it appears to be an integer
Double_Type : If it appears to be a double
String_Type : Anything else.
For example,
_slang_guess_type("1e2") returns
Double_Type but
_slang_guess_type("e12") returns
String_Type .
See also
Synopsis
Get the data type of an object
Usage
DataType_Type _typeof (x)
Description
This function is similar to the
typeof function except in the
case of arrays. If the object
x is an array, then the data
type of the array will be returned. otherwise
_typeof returns
the data type of
x .
Example
if (Integer_Type == _typeof (x))
message ("x is an integer or an integer array");
See also
function atof
Synopsis
Convert a string to a double precision number
Usage
Double_Type atof (String_Type s)
Description
This function converts a string
s to a double precision value
and returns the result. It performs no error checking on the format
of the string. The function
_slang_guess_type may be used to
check the syntax of the string.
Example
define error_checked_atof (s)
{
switch (_slang_guess_type (s))
{
case Double_Type:
return atof (s);
}
{
case Integer_Type:
return double (integer (s));
}
verror ("%s is is not a double", s);
}
See also
function char
Synopsis
Convert an ascii value into a string
Usage
String_Type char (Integer_Type c)
Description
The char function converts an integer ascii value c to a string
of unit length such that the first character of the string is c .
For example, char('a') returns the string "a" .
See also
Synopsis
Define upper-lower case conversion.
Usage
define_case (Integer_Type ch_up, Integer_Type ch_low);
Description
This function defines an upper and lowercase relationship between two
characters specified by the arguments. This relationship is used by
routines which perform uppercase and lowercase conversions.
The first integer ch_up is the ascii value of the uppercase character
and the second parameter ch_low is the ascii value of its
lowercase counterpart.
See also
Synopsis
Convert an object to double precision
Usage
result = double (x)
Description
The double function typecasts an object x to double
precision. For example, if x is an array of integers, an
array of double types will be returned. If an object cannot be
converted to Double_Type , a type-mismatch error will result.
Notes
The
double function is equivalent to the typecast operation
typecast (x, Double_Type)
To convert a string to a double precision number, use
atoi
function.
See also
function int
Synopsis
Typecast an object to an integer
Usage
int (s)
Description
This function performs a typecast of s from its data type to
an object of Integer_Type . If s is a string, it returns
returns the ascii value value of the first character of the string
s . If s is Double_Type , int truncates the
number to an integer and returns it.
Example
int can be used to convert single character strings to
integers. As an example, the intrinsic function
isdigit may
be defined as
define isdigit (s)
{
if ((int (s) >= '0') and (int (s) <= '9')) return 1;
return 0;
}
Notes
This function is equalent to typecast (s, Integer_Type) ;
See also
Synopsis
Convert a string to an integer
Usage
Integer_Type integer (String_Type s)
Description
The integer function converts a string representation of an
integer back to an integer. If the string does not form a valid
integer, a type-mismatch error will be generated.
Example
integer ("1234") returns the integer value 1234 .
Notes
This function operates only on strings and is not the same as the
more general
typecast operator.
See also
Synopsis
Tests for a decimal digit character
Usage
Integer_Type isdigit (String_Type s)
Description
This function returns a non-zero value if the first character in the
string s is a digit; otherwise, it returns zero.
Example
A simple, user defined implementation of
isdigit is
define isdigit (s)
{
return ((s[0] <= '9') and (s[0] >= '0'));
}
However, the intrinsic function
isdigit executes many times faster
than the equivalent representation defined above.
Notes
Unlike the C function with the same name, the SLang function takes
a string argument.
See also
Synopsis
Convert an object to a string representation.
Usage
Integer_Type string (obj)
Description
The string function may be used to convert an object
obj of any type to a string representation.
For example, string(12.34) returns "12.34" .
Example
define print_anything (anything)
{
message (string (anything));
}
Notes
This function is
not the same as typecasting to a
String_Type
using the
typecast function.
See also
Synopsis
Convert a character to lowercase.
Usage
Integer_Type lower (Integer_Type ch)
Description
This function takes an integer ch and returns its lowercase
equivalent.
See also
Synopsis
Convert a character to uppercase.
Usage
Integer_Type toupper (Integer_Type ch)
Description
This function takes an integer ch and returns its uppercase
equivalent.
See also
Synopsis
Convert an object from one data type to another.
Usage
typecast (x, new_type)
Description
The typecast function performs a generic typecast operation on
x to convert it to new_type . If x represents an
array, the function will attempt to convert all elements of x
to new_type . Not all objects can be converted and a
type-mismatch error will result upon failure.
Example
define to_complex (x)
{
return typecast (x, Complex_Type);
}
defines a function that converts its argument,
x to a complex
number.
See also
Synopsis
Get the data type of an object.
Usage
DataType_Type typeof (x)
Description
This function returns the data type of x .
Example
if (Integer_Type == typeof (x)) message ("x is an integer");
See also