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############################################################################
#
# File: interpe.icn
#
# Subject: Program to interpret Icon expressions
#
# Author: Ralph E. Griswold
#
# Date: December 30, 1991
#
############################################################################
#
# This file is in the public domain.
#
############################################################################
#
# This program is a crude but effective interpreter for Icon expressions.
# Each line entered from standard input is presumed to be an Icon
# expression, is wrapped with a main procedure, and written to a pipe
# that compiles and executes the resulting program.
#
# If the expression is a generator, all its results are produced.
# If the command-line option -e is given, the expression is echoed.
#
# This technique is, of course, inefficient and may be painfully
# slow except on the fastest platforms. This technique is, however,
# completely general and as correct as Icon itself.
#
# Note: This programs creates files with the names stdin, stdin.u1,
# and stdin.u2. It removes them before terminating, but, of course,
# overwrites any pre-existing files by these names.
#
############################################################################
#
# Requires: UNIX
#
# See also: interpp.icn
#
############################################################################
procedure main(args)
local line, run, echo
if args[1] == "-e" then echo := 1
while line := read() do {
run := open("icont -s - -x","pw")
write(run,"procedure main()")
if \echo then write(run," write(",image(line),")")
write(run," every write(image(",line,"))")
write(run,"end")
close(run)
}
system("rm -f stdin stdin.u1 stdin.u2")
end
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