System Functions and Variables

[]CR Display Function

Given a function name as right parameter, []CR returns the source code of the function in a character matrix. The extra space in a line will be filled with blanks.

[]CR 'function name' //two quotes are required

[]open and []close

h<-[]open v	Open a file and start file stream
t<-[]close h	Close file stream with specified file handler
v	String, presents the path of the designated file
h	File handler with integer value greater equal than 1000

Usually, []open and []close are used in pairs. []open opens a file and saves a handler for file streaming and []close safely closes the file stream at the end of writing. []open allows multiple file open on a same file, but a different file handler will be returned. []close checks the file handler before it is closed. If it is a valid one, it will be closed immediately with return value 0. Otherwise, an integer 1 should be returned.

[]RL Random Link

[]RL	Output the current random seed
[]RL<-v	Set random seed for random number generator
v	Positive integer scalar
Default value	16807

      []RL
16807
      ?.100
14
      []RL
282475249
      ?.100
76

      []RL
16807
      5?.100
14 76 46 54 22
      []RL
470211272
      5?.100
5 68 94 39 52

After the random number is generated with a random seed ([]RL), []RL is reset for next computation.

      []RL<-16807
      []RL
16807
      ?.100
14

[]PP Printing Precision

[]PP<-V	Set the precision of printing for floating point and complex number
V	Positive integer scalar
Default value	10

[]PP is a system variable and its value should be greater than 0. On the other words, the minimal value of []PP is 1. []PP controls the output precision of the floating point and complex number.

      []PP
10
      1%3
0.3333333333
      []PP<-6
      1%3
0.333333

      []PP
10
      2j3%3
0.6666666667j1
      []PP<-6
      2j3%3
0.666667j1

Except floating point and complex number, []PP does not take effect on integer and any other types.

      []PP<-1
      333
333
      333.0
3e2