Addition documentation explaining aritmetic negation on strings. Also,

additional test cases based partially on code by Piotr Fusik in 
RT #36675: -'-10' eq '+10'.

p4raw-id: //depot/perl@26387

1 files changed, 31 insertions, 0 deletions

diff --git a/t/op/negate.t b/t/op/negate.t
new file mode 100644
index 0000000000..fb8d4b49e8
--- /dev/null
+++ b/t/op/negate.t
@@ -0,0 +1,31 @@
+#!./perl -w
+
+BEGIN {
+    chdir 't' if -d 't';
+    @INC = '../lib';
+    require './test.pl';
+}
+
+plan tests => 16;
+
+# Some of these will cause warnings if left on.  Here we're checking the
+# functionality, not the warnings.
+no warnings "numeric";
+
+# test cases based on [perl #36675] -'-10' eq '+10'
+is(- 10, -10, "Simple numeric negation to negative");
+is(- -10, 10, "Simple numeric negation to positive");
+is(-"10", -10, "Negation of a positive string to negative");
+is(-"10.0", -10, "Negation of a positive decimal sting to negative");
+is(-"10foo", -10, "Negation of a numeric-lead string returns negation of numeric");
+is(-"-10", "+10", 'Negation of string starting with "-" returns a string starting with "+" - numeric');
+is(-"-10.0", "+10.0", 'Negation of string starting with "-" returns a string starting with "+" - decimal');
+is(-"-10foo", "+10foo", 'Negation of string starting with "-" returns a string starting with "+" - non-numeric');
+is(-"xyz", "-xyz", 'Negation of a negative string adds "-" to the front');
+is(-"-xyz", "+xyz", "Negation of a negative string to positive");
+is(-"+xyz", "-xyz", "Negation of a positive string to negative");
+is(-bareword, "-bareword", "Negation of bareword treated like a string");
+is(- -bareword, "+bareword", "Negation of -bareword returns string +bareword");
+is(-" -10", 10, "Negation of a whitespace-lead numeric string");
+is(-" -10.0", 10, "Negation of a whitespace-lead decimal string");
+is(-" -10foo", 10, "Negation of a whitespace-lead sting starting with a numeric")