Fix abort on boolean negation/plus unary operators

Currently jimtcl will abort if there is any unary operator besides ! in
front of a boolean.  It is possible to construct an expression with -
or + before a boolean literal (e.g. expr {-true}) that currently aborts,
but should return an error.  I implemented this error handling with
tcl's error message for this situation.

2 files changed, 14 insertions, 0 deletions

diff --git a/jim.c b/jim.c
index fe22e79..d49a205 100644
--- a/jim.c
+++ b/jim.c
@@ -8452,6 +8452,13 @@ static int JimExprOpNumUnary(Jim_Interp *interp, struct JimExprNode *node)
             case JIM_EXPROP_NOT:
                 wC = !bA;
                 break;
+            case JIM_EXPROP_UNARYPLUS:
+            case JIM_EXPROP_UNARYMINUS:
+                rc = JIM_ERR;
+                Jim_SetResultFormatted(interp,
+                    "can't use non-numeric string as operand of \"%s\"",
+                        node->type == JIM_EXPROP_UNARYPLUS ? "+" : "-");
+                break;
             default:
                 abort();
         }
diff --git a/tests/expr.test b/tests/expr.test
index 7e26c0a..bc52afd 100644
--- a/tests/expr.test
+++ b/tests/expr.test
@@ -154,5 +154,12 @@ test expr-5.3 {boolean in expression} {
 	expr {true ? 4 : 5}
 } {4}
 
+test expr-6.1 "Unary negation on boolean - should return error" -body {
+	expr {-true}
+} -returnCodes error -result {can't use non-numeric string as operand of "-"}
+
+test expr-6.2 "Unary plus on boolean - should return error" -body {
+	expr {+true}
+} -returnCodes error -result {can't use non-numeric string as operand of "+"}
 
 testreport