What's different about defind class method?

Ruby
1

A.class_eval(<<-EOF, FILE, LINE)
def method_a
puts “calling method_a…”
end
EOF

A.class_eval <<-EOF
def method_b
puts “calling method_b…”
end
EOF

A.new.method_a
A.new.method_b

Why lot of Rails snippet code use FILE LINE

2

bill gate wrote in post #1064388:

Why lot of Rails snippet code use FILE LINE

FILE and LINE are magic constants. They point to the file/line
they’re in.

In combination with class_eval these constants can be used to produce
exact error messages. If you don’t use them, an error message within the
class_eval will only display the file and line of the “class_eval”.

See

3

Jan E. wrote in post #1064399:

bill gate wrote in post #1064388:

Why lot of Rails snippet code use FILE LINE

FILE and LINE are magic constants. They point to the file/line
they’re in.

In combination with class_eval these constants can be used to produce
exact error messages. If you don’t use them, an error message within the
class_eval will only display the file and line of the “class_eval”.

See
Class: Module (Ruby 1.9.3)

Greate, Thank you.