perl 1.0 patch 8: perl needed an eval operator and a symbolic debugger

I didn't add an eval operator to the original perl because
I hadn't thought of any good uses for it.  Recently I thought
of some.  Along with creating the eval operator, this patch
introduces a symbolic debugger for perl scripts, which makes
use of eval to interpret some debugging commands.  Having eval
also lets me emulate awk's FOO=bar command line behavior with
a line such as the one a2p now inserts at the beginning of
translated scripts.

2 files changed, 31 insertions, 2 deletions

diff --git a/t/base.lex b/t/base.lex
index 2cfe311ed8..015f442c77 100644
--- a/t/base.lex
+++ b/t/base.lex
@@ -1,8 +1,8 @@
 #!./perl
 
-# $Header: base.lex,v 1.0 87/12/18 13:11:51 root Exp $
+# $Header: base.lex,v 1.0.1.1 88/01/28 10:37:00 root Exp $
 
-print "1..4\n";
+print "1..6\n";
 
 $ # this is the register <space>
 = 'x';
@@ -21,3 +21,12 @@ if ($x eq '-1') {print "ok 3\n";} else {print "not ok 3\n";}
 $x = '\\'; # ';
 
 if (length($x) == 1) {print "ok 4\n";} else {print "not ok 4\n";}
+
+eval 'while (0) {
+    print "foo\n";
+}
+/^/ && (print "ok 5\n");
+';
+
+eval '$foo{1} / 1;';
+if (!$@) {print "ok 6\n";} else {print "not ok 6\n";}
diff --git a/t/op.eval b/t/op.eval
new file mode 100644
index 0000000000..191571015c
--- /dev/null
+++ b/t/op.eval
@@ -0,0 +1,20 @@
+#!./perl
+
+print "1..6\n";
+
+eval 'print "ok 1\n";';
+
+if ($@ eq '') {print "ok 2\n";} else {print "not ok 2\n";}
+
+eval "\$foo\n    = # this is a comment\n'ok 3';";
+print $foo,"\n";
+
+eval "\$foo\n    = # this is a comment\n'ok 4\n';";
+print $foo;
+
+eval '
+$foo =';		# this tests for a call through yyerror()
+if ($@ =~ /line 2/) {print "ok 5\n";} else {print "not ok 5\n";}
+
+eval '$foo = /';	# this tests for a call through fatal()
+if ($@ =~ /Search/) {print "ok 6\n";} else {print "not ok 6\n";}