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5.1.128 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 a string. If the ASCII link is the empty string,
read reads from standard input.
For ssi links, one expression is read
from the link and returned after evaluation. See Ssi links.
For ssi 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. See DBM links.
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
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See
execute;
getdump;
link;
status;
write.
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