slangfun.txt

一个C格式的脚本处理函数库源代码,可让你的C程序具有执行C格式的脚本文件

 DESCRIPTION
   The `exp' function computes the exponential of a number and
   returns the result as an array.  If its argument is an array, the
   `exp' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   cos, atan, acosh, cosh
--------------------------------------------------------------

log

 SYNOPSIS
   Compute the logarithm of an number

 USAGE
   y = log (x)

 DESCRIPTION
   The `log' function computes the logarithm of a number and
   returns the result as an array.  If its argument is an array, the
   `log' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   cos, atan, acosh, cosh
--------------------------------------------------------------

log10

 SYNOPSIS
   Compute the base-10 logarithm of an number

 USAGE
   y = log10 (x)

 DESCRIPTION
   The `log10' function computes the base-10 logarithm of a number and
   returns the result as an array.  If its argument is an array, the
   `log10' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   cos, atan, acosh, cosh
--------------------------------------------------------------

mul2

 SYNOPSIS
   Multiply a number by 2

 USAGE
   y = mul2(x)

 DESCRIPTION
   The `mul2' function multiplies an arithmetic type by two and
   returns the result.  If its argument is an array, a new array will
   be created whose elements are obtained from the original array by
   using the `mul2' function.

 SEE ALSO
   sqr, abs
--------------------------------------------------------------

polynom

 SYNOPSIS
   Evaluate a polynomial

 USAGE
   Double_Type polynom(Double_Type a, b, ...c, Integer_Type n, Double_Type x)

 DESCRIPTION
   The `polynom' function returns the value of the polynomial expression:

        ax^n + bx^(n - 1) + ... c


 NOTES
   The `polynom' function should be extended to work with complex
   and array data types.  The current implementation is limited to
   `Double_Type' quantities.

 SEE ALSO
   exp
--------------------------------------------------------------

set_float_format

 SYNOPSIS
   Set the format for printing floating point values.

 USAGE
   set_float_format (String_Type fmt)

 DESCRIPTION
   The `set_float_format' function is used to set the floating
   point format to be used when floating point numbers are printed.
   The routines that use this are the traceback routines and the
   `string' function. The default value is `"%f"'

 EXAMPLE

        s = string (PI);                %  --> s = "3.14159"
        set_float_format ("%16.10f");
        s = string (PI);                %  --> s = "3.1415926536"
        set_float_format ("%10.6e");
        s = string (PI);                %  --> s = "3.141593e+00"


 SEE ALSO
   string, sprintf, double
--------------------------------------------------------------

sign

 SYNOPSIS
   Compute the sign of a number

 USAGE
   y = sign(x)

 DESCRIPTION
   The `sign' function returns the sign of an arithmetic type.  If
   its argument is a complex number (`Complex_Type'), it returns
   the sign of the imaginary part of the number. If the argument is an
   array, a new array will be created whose elements are obtained from
   the original array by using the `sign' function.
   
   When applied to a real number or an integer, the `sign' function
   returns -1, 0, or `+1' according to whether the number is
   less than zero, equal to zero, or greater than zero, respectively.

 SEE ALSO
   abs
--------------------------------------------------------------

sin

 SYNOPSIS
   Compute the sine of an number

 USAGE
   y = sin (x)

 DESCRIPTION
   The `sin' function computes the sine of a number and
   returns the result as an array.  If its argument is an array, the
   `sin' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   cos, atan, acosh, cosh
--------------------------------------------------------------

sinh

 SYNOPSIS
   Compute the hyperbolic sine of an number

 USAGE
   y = sinh (x)

 DESCRIPTION
   The `sinh' function computes the hyperbolic sine of a number and
   returns the result as an array.  If its argument is an array, the
   `sinh' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   cos, atan, acosh, cosh
--------------------------------------------------------------

sqr

 SYNOPSIS
   Compute the square of a number

 USAGE
   y = sqr(x)

 DESCRIPTION
   The `sqr' function returns the square of an arithmetic type.  If its
   argument is a complex number (`Complex_Type'), then it returns
   the square of the modulus.  If the argument is an array, a new array
   will be created whose elements are obtained from the original array
   by using the `sqr' function.

 SEE ALSO
   abs, mul2
--------------------------------------------------------------

sqrt

 SYNOPSIS
   Compute the square root of an number

 USAGE
   y = sqrt (x)

 DESCRIPTION
   The `sqrt' function computes the square root of a number and
   returns the result as an array.  If its argument is an array, the
   `sqrt' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   sqr, cos, atan, acosh, cosh
--------------------------------------------------------------

tan

 SYNOPSIS
   Compute the tangent of an number

 USAGE
   y = tan (x)

 DESCRIPTION
   The `tan' function computes the tangent of a number and
   returns the result as an array.  If its argument is an array, the
   `tan' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   cos, atan, acosh, cosh
--------------------------------------------------------------

tanh

 SYNOPSIS
   Compute the hyperbolic tangent of an number

 USAGE
   y = tanh (x)

 DESCRIPTION
   The `tanh' function computes the hyperbolic tangent of a number and
   returns the result as an array.  If its argument is an array, the
   `tanh' function will be applied to each element and the result returned
   as an array.

 SEE ALSO
   cos, atan, acosh, cosh
--------------------------------------------------------------

error

 SYNOPSIS
   Generate an error condition

 USAGE
   error (String_Type msg

 DESCRIPTION
   The `error' function generates a S-Lang error condition causing
   the interpreter to start unwinding to top-level.  It takes a single
   string parameter which is displayed on the stderr output device.
   The error condition may be cleared via an `ERROR_BLOCK' with the
   `_clear_error' function.  Consult \user-manual for more
   information.

 EXAMPLE

       define add_txt_extension (file)
       {
          if (typeof (file) != String_Type)
            error ("add_extension: parameter must be a string");
          file += ".txt";
          return file;
       }


 SEE ALSO
   verror, _clear_error, message
--------------------------------------------------------------

message

 SYNOPSIS
   Print a string onto the message device

 USAGE
   message (String_Type s

 DESCRIPTION
   The `message' function will print the string specified by
   `s' onto the message device.

 EXAMPLE

        define print_current_time ()
        {
          message (time ());
        }


 NOTES
   The message device will depend upon the application.  For example,
   the output message device for the `jed' editor correspond to the
   line at the bottom of the display window.  The default message
   device is the standard output device.

 SEE ALSO
   vmessage, sprintf, error
--------------------------------------------------------------

usage

 SYNOPSIS
   Generate a usage error

 USAGE
   usage (String_Type msg)

 DESCRIPTION
   The `usage' function generates a usage exception and displays
   `msg' to the message device.

 EXAMPLE
   Suppose that some function `plot' plots an array of `x' and
   `y' values.  The such a function could be written to issue a
   usage message if the wrong number of arguments were passed:

       define plot ()
       { 
          variable x, y;
   
          if (_NARGS != 2)
            usage ("plot (x, y)");
          
          (x, y) = ();
          % Now do the hard part
             .
   	  .
       }


 SEE ALSO
   error, message
--------------------------------------------------------------

verror

 SYNOPSIS
   Generate an error condition

 USAGE
   verror (String_Type fmt, ...)

 DESCRIPTION
   The `verror' function performs the same role as the `error'
   function.  The only difference is that instead of a single string
   argument, `verror' takes a sprintf style argument list.

 EXAMPLE

       define open_file (file)
       {
          variable fp;
   
          fp = fopen (file, "r");
          if (fp == NULL) verror ("Unable to open %s", file);
          return fp;
       }


 NOTES
   In the current implementation, strictly speaking, the `verror'
   function is not an intrinsic function.  Rather it is a predefined
   S-Lang function using a combination of `Sprintf' and
   `error'.

 SEE ALSO
   error, Sprintf, vmessage
--------------------------------------------------------------

vmessage

 SYNOPSIS
   Print a formatted string onto the message device

 USAGE
   vmessage (String_Type fmt, ...)

 DESCRIPTION
   The `vmessage' function formats a sprintf style argument list
   and displays the resulting string onto the message device.

 NOTES
   In the current implementation, strictly speaking, the `vmessage'
   function is not an intrinsic function.  Rather it is a predefined
   S-Lang function using a combination of `Sprintf' and
   `message'.

 SEE ALSO
   message, Sprintf, verror
--------------------------------------------------------------

__class_id

 SYNOPSIS
   Return the class-id of a specified type

 USAGE
   Int_Type __class_id (DataType_Type type))

 DESCRIPTION
   This function returns the internal class-id of a specified data type.

 SEE ALSO
   typeof, _typeof, __class_type
--------------------------------------------------------------

__class_type

 SYNOPSIS
   Return the class-type of a specified type

 USAGE
   Int_Type __class_type (DataType_Type type))

 DESCRIPTION
   Internally S-Lang objects are classified according to four types:
   scalar, vector, pointer, and memory managed types.  For example, an
   integer is implemented as a scalar, a complex number as a vector,
   and a string is represented as a pointer.  The `__class_type'
   function returns an integer representing the class-type associated
   with the specified data type. Specifically, it returns:

          0    memory-managed
          1    scalar
          2    vector
          3    pointer


 SEE ALSO
   typeof, _typeof, __class_id
--------------------------------------------------------------

__eqs

 SYNOPSIS
   Test for equality between two objects

 USAGE
   Int_Type __eqs (a, b)

 DESCRIPTION
   This function tests its two arguments for equalit and returns 1
   if they are equal, and 0 otherwise.  To be equal, the data type of
   the arguments must match and the values of the objects must
   reference the same underlying object.

 EXAMPLE
   __eqs (1, 1)         ===> 1
   __eqs (1, 1.0)       ===> 0
   __eqs ("a", 1)       ===> 0
   __eqs ([1,2], [1,2]) ===> 0

 SEE ALSO
   typeof, __get_reference

 NOTES
   This function should be thought of as a test for "sameness".
--------------------------------------------------------------

__get_reference

 SYNOPSIS
   Get a reference to a global object

 USAGE
   Ref_Type __get_reference (String_Type nm)

 DESCRIPTION
   This function returns a reference to a global variable or function
   whose name is specified by `nm'.  If no such object exists, it
   returns `NULL', otherwise it returns a reference.

 EXAMPLE
   For example, consider the function:

       define runhooks (hook)
       {
          variable f;
          f = __get_reference (hook);
          if (f != NULL)
            @f ();
       }

   This function could be called from another S-Lang function to
   allow customization of that function, e.g., if the function
   represents a mode, the hook could be called to setup keybindings
   for the mode.

 SEE ALSO
   is_defined, typeof, eval, autoload, __is_initialized, __uninitialize
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