parsing literals

[ako...]

hello,

i need to write a function that would parse a string literal in another
language. a string literal in this language is:

STRING = "CHAR*"
CHAR = any character except for " and \
| \"
| \\
| \/
| \u four hexadecimal digits

the \u sequence specifies a character in UTF-16 encoding.

for example: "abc", "", "a\"bc", "a\\b", "a\u12bfc"

below is the code that i wrote. is this Ruby enough? can someone
suggest improvements? a better style?

thanks
konstantin

def parselit(s)
r = %r{\\"|\\/|\\\\|\\u[\da-f][\da-f][\da-f][\da-f]}i
s =~ /^"((?:[^"\\]|#{r})*)"$/ && $1.gsub(r) { |x| x =~ /\\u(.*)/ ?
[$1.hex].pack('U*') : x[1..-1] }
end

puts parselit('"\u004e\"a"')

 

[William James]

hello,

i need to write a function that would parse a string literal in another
language. a string literal in this language is:

STRING = "CHAR*"
CHAR = any character except for " and \
| \"
| \\
| \/
| \u four hexadecimal digits

the \u sequence specifies a character in UTF-16 encoding.

for example: "abc", "", "a\"bc", "a\\b", "a\u12bfc"

below is the code that i wrote. is this Ruby enough? can someone
suggest improvements? a better style?

thanks
konstantin

def parselit(s)
r = %r{\\"|\\/|\\\\|\\u[\da-f][\da-f][\da-f][\da-f]}i
s =~ /^"((?:[^"\\]|#{r})*)"$/ && $1.gsub(r) { |x| x =~ /\\u(.*)/ ?
[$1.hex].pack('U*') : x[1..-1] }
end

puts parselit('"\u004e\"a"')

def parselit(s)

re = %r{
\\"
| \\/
| \\\\
| \\u [\da-f] {4}
}xoi

return nil if s !~ /^".*"$/

out = ""

s[1..-2].scan( /\G (?: ( [^"\\]+ ) | ( #{re} ) )/x ){ |x|
out <<
if !x.last
x.first
else
if x.last[0,2] == '\u'
[x.last[2..-1].hex].pack('U*')
else
x.last[1..-1]
end
end

}

# Fail if whole string didn't match.
if $~.post_match != ""
nil
else
out
end


end

puts parselit('"\u004e\"a"')
puts parselit('"\u004e\""a"')