Top
Back: random
Forward: reduce
FastBack: Functions and system variables
FastForward: Control structures
Up: Functions
Top: Singular 2-0-4 Manual
Contents: Table of Contents
Index: Index
About: About this document

5.1.105 read

Syntax:
read ( link_expression )
for DBM links:
read ( link_expression )
read ( link_expression, string_expression )
Type:
any
Purpose:
reads data from a link.
For ASCII links, the content of the entire file is returned as one string. If the ASCII link is the empty string, read reads from standard input.
For MP links, one expression is read from the link and returned after evaluation.
For MPtcp links the read command blocks as long as there is no data to be read from the link. The status command can be used to check whether or not there is data to be read.
For DBM links, a read with one argument returns the value of the next entry in the data base, and a read with two arguments returns the value to the key given as the second argument from the data base.
Example:
 
  ring r=32003,(x,y,z),dp;
  ideal i=x+y,z3+22y;
  // write the ideal i to the file save_i
  write(":w save_i",i);
  ring r0=0,(x,y,z),Dp;
  // create an ideal k equal to the content
  // of the file save_i
  string s="ideal k="+read("save_i")+";";
  execute(s);
  k;
==> k[1]=x+y
==> k[2]=z3+22y
See execute; getdump; link; status; write.

Top Back: random Forward: reduce FastBack: Functions and system variables FastForward: Control structures Up: Functions Top: Singular 2-0-4 Manual Contents: Table of Contents Index: Index About: About this document
            User manual for Singular version 2-0-4, May 2003, generated by texi2html.