Description: Documentation

## function _slang_guess_type

### 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

integer , string , double

## function _typeof

### 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

typeof , array_info , _slang_guess_type , typecast

## 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

typecast , double , _slang_guess_type

## 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

integer , string , typedef

## function define_case

### 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

strlow , strup

## function double

### 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

typecast , atoi, int

## 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

typecast , double , integer , char , isdigit

## function integer

### 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

typecast , _slang_guess_type , string , sprintf , char

## function isdigit

### 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

int , integer

## function string

### 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

typecast , sprintf , integer , char

## function tolower

### 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

toupper , strup , strlow , int , char , define_case

## function toupper

### 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

tolower , strup , strlow , int , char , define_case

## function typecast

### 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

int , double , typeof

## function typeof

### 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

_typeof , is_struct_type , array_info , _slang_guess_type , typecast