Throw exception when Range endpoint is used to create a Range.

rakudo · Mar 16, 2013 · ff346ad · ff346ad
1 parent ce914fc
commit ff346ad
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Showing 2 changed files with 26 additions and 12 deletions.
diff --git a/src/core/Exception.pm b/src/core/Exception.pm
@@ -968,6 +968,13 @@ my class X::Str::Trans::InvalidArg is Exception {
     }
 }
 
+my class X::Range::InvalidArg is Exception {
+    has $.got;
+    method message() {
+        "{$.got.^name} objects are not valid endpoints for Ranges";
+    }
+}
+
 my class X::Sequence::Deduction is Exception {
     method message() { 'Unable to deduce sequence' }
 }

diff --git a/src/core/Range.pm b/src/core/Range.pm
@@ -1,29 +1,36 @@
-class Range is Iterable is Cool does Positional {
+my class X::Range::InvalidArg { ... }
+
+my class Range is Iterable is Cool does Positional {
     has $.min;
     has $.max;
     has $.excludes_min;
     has $.excludes_max;
 
     proto method new(|) { * }
-    multi method new($min, $max, :$excludes_min, :$excludes_max) {
-        nqp::create(self).BUILD($min, $max, $excludes_min, $excludes_max)
+    # The order of "method new" declarations matters here, to ensure
+    # appropriate candidate tiebreaking when mixed type arguments 
+    # are present (e.g., Range,Whatever or Real,Range).
+    multi method new(Range $min, $max, :$excludes_min, :$excludes_max) {
+        X::Range::InvalidArg.new(:got($min)).throw;
     }
-    multi method new(Real $min, $max, :$excludes_min, :$excludes_max) {
-        nqp::create(self).BUILD($min, $max.Real, $excludes_min, $excludes_max)
+    multi method new($min, Range $max, :$excludes_min, :$excludes_max) {
+        X::Range::InvalidArg.new(:got($max)).throw;
     }
-    multi method new(Real $min, Whatever $max, :$excludes_min, :$excludes_max) {
-        nqp::create(self).BUILD($min, $Inf, $excludes_min, $excludes_max)
+    multi method new(Whatever $min, Whatever $max, :$excludes_min, :$excludes_max) {
+        fail "*..* is not a valid range";
+    }
+    multi method new(Whatever $min, $max, :$excludes_min, :$excludes_max) {
+        nqp::create(self).BUILD(-$Inf, $max, $excludes_min, $excludes_max)
     }
     multi method new($min, Whatever $max, :$excludes_min, :$excludes_max) {
         nqp::create(self).BUILD($min, $Inf, $excludes_min, $excludes_max)
     }
-    multi method new(Whatever $min, $max, :$excludes_min, :$excludes_max) {
-        nqp::create(self).BUILD(-$Inf, $max, $excludes_min, $excludes_max)
+    multi method new(Real $min, $max, :$excludes_min, :$excludes_max) {
+        nqp::create(self).BUILD($min, $max.Real, $excludes_min, $excludes_max)
     }
-    multi method new(Whatever $min, Whatever $max, :$excludes_min, :$excludes_max) {
-        fail "*..* is not a valid range";
+    multi method new($min, $max, :$excludes_min, :$excludes_max) {
+        nqp::create(self).BUILD($min, $max, $excludes_min, $excludes_max)
     }
-
 
     submethod BUILD($min, $max, $excludes_min, $excludes_max) {
         $!min = $min;