I need Ruby to parse and edit parts of files with a custom syntax - ruby

Question

I have a set of .txt files that show a custom languange, files I want to systematically modify using a Ruby script. The syntax of that language is as follows:
(I will use [some text] as meta variables for expressions, like [atom 1] to indicate an arbitrary atom, and [atom 2] to indicate an arbitrary atom diferent from the former)
Atoms: alphanumerical strings, possibly surrounded by double quotes. Examples:
same_realm
"Ok"
Statements: either
[atom_1] = [atom_2]
or
[atom_1] = { [atom or statement 1] ... [atom or statement n] }
comments: in any line of the text, any character after a # is ignored. Example:
[atom_1] = [atom_2] #This is a comment and will be ignored
If an statement is of the form [atom 1] = {[atom or statement 1] ... [atom or statement n]}, we call [atom 1] the head of the satement and [atom or statement 1] ... [atom or statement n] the body of the statement.
Before and after =, { and } there can be an arbitrary number (possibly 0) of space characters.
Between two consecutive atoms must be at least one space character, but can be any number higher than that.
So, the two expressions any_realm_lord = {...} and any_realm_lord = {...} in the example below are valid, the only syntactical difference between them being the use of any_realm_lord/any_province_lord as the head of each statement.
#Example file
#previous text
any_realm_lord={any_character={limit={same_realm=ROOT}set_character_flag=my_flag}
} any_province_lord={any_character = { #some comment
limit = {#some other comment
same_realm = ROOT} set_character_flag =
my_flag
}
}#more text
Once that's explained, this is what I want to do with ruby (I will use the Example file above to illustrate it)
1) Open a file and locate the statements which are not within the body of other statements
(in the example, I'd want it to locate the any_realm_character = {...} and the any_province_character = {...} statements)
2) Iterate over the statements located in 1) and select the ones whose head matches a certain string. If the match is in a line where there is also other atoms or statements, separate them. From now on, I will refer to the statement whose head matches the string as "the target statement".
(Say the string to match is "any_province_lord". After this step the file will look like this:
#Example file
#previous text
any_realm_lord={any_character={limit={same_realm=ROOT}set_character_flag=my_flag}
}
any_province_lord={any_character = { #some comment
limit = {#some other comment
same_realm = ROOT} set_character_flag =
my_flag
}
}#more text
)
3) create a blank line above the line where the head of the target statement is, and cut and paste there any comment in the lines that the target statement encompass
(
#Example file
#previous text
any_realm_lord={any_character={limit={same_realm=ROOT}set_character_flag=my_flag}
}
#some comment#some other comment
any_province_lord={any_character = {
limit = {
same_realm = ROOT} set_character_flag =
my_flag
}
}#more text
)
4)If the closing bracket of the target statement is in the same line as another atom(s) or statement(s), add a \n after the closing bracket
(
#Example file
#previous text
any_realm_lord={any_character={limit={same_realm=ROOT}set_character_flag=my_flag}
}
#some comment#some other comment
any_province_lord={any_character = {
limit = {
same_realm = ROOT} set_character_flag =
my_flag
}
}
#more text
)
5)Erase the body of the target statement (but not the brackets), and add new content between the brackets that I have already defined, with nice spacing.
(
#Example file
#previous text
any_realm_lord={any_character={limit={same_realm=ROOT}set_character_flag=my_flag}
}
#some comment#some other comment
any_province_lord={
#my predefined content will be here
}
#more text
)
What would then be the best way to do this in terms of efficiency? I need my program to do this to over a thousand of files (each one of an average size of 500Kb). I'm fairly new to Ruby, so I am still figuring out if for these things is best to use read, readlines, or readline in term of efficiency.
What do you think?
I hope I've been clear in the explanation of what I need and not too unnecesarily verbose