Check modifiable for String `bang' methods
MODIFY
mrbgems/mruby-string-ext/mrblib/string.rb
mrbgems/mruby-string-ext/mrblib/string.rb
@@ -95,6 +95,7 @@ class String
# "hello".lstrip! #=> nil
#
def lstrip!
+ raise RuntimeError, "can't modify frozen String" if frozen?
s = self.lstrip
(s == self) ? nil : self.replace(s)
end
@@ -111,6 +112,7 @@ class String
# "hello".rstrip! #=> nil
#
def rstrip!
+ raise RuntimeError, "can't modify frozen String" if frozen?
s = self.rstrip
(s == self) ? nil : self.replace(s)
end
@@ -123,6 +125,7 @@ class String
# <code>nil</code> if <i>str</i> was not altered.
#
def strip!
+ raise RuntimeError, "can't modify frozen String" if frozen?
s = self.strip
(s == self) ? nil : self.replace(s)
end
@@ -183,6 +186,7 @@ class String
# string #=> "thsa sting"
#
def slice!(arg1, arg2=nil)
+ raise RuntimeError, "can't modify frozen String" if frozen?
raise "wrong number of arguments (for 1..2)" if arg1.nil? && arg2.nil?
if !arg1.nil? && !arg2.nil?

MODIFY
mrblib/string.rb
mrblib/string.rb
@@ -78,6 +78,7 @@ class String
#
# ISO 15.2.10.5.19
def gsub!(*args, &block)
+ raise RuntimeError, "can't modify frozen String" if frozen?
str = self.gsub(*args, &block)
return nil if str == self
self.replace(str)
@@ -123,6 +124,7 @@ class String
#
# ISO 15.2.10.5.37
def sub!(*args, &block)
+ raise RuntimeError, "can't modify frozen String" if frozen?
str = self.sub(*args, &block)
return nil if str == self
self.replace(str)

Check modifiable for String `bang' methods