First working versions.

Manifest.toml

+# This file is machine-generated - editing it directly is not advised
+
+julia_version = "1.11.6"
+manifest_format = "2.0"
+project_hash = "da39a3ee5e6b4b0d3255bfef95601890afd80709"
+
+[deps]

Project.toml

+name = "GeneratedFiles"
+uuid = "dd08c5e9-7c90-4908-81e2-08ae9a8bbe49"
+authors = ["Antonino <anda982008@gmail.com>"]
+version = "0.1.0"

src/#types.jl#

+mutable struct Tag
+    tag::String
+    #=
+    Order records by position. if pos<0 they are put at the end of the list.
+    =#
+    pos::Int64 ##
+    Tag(s, pos) = new(s,pos)
+    Tag(s) = Tag(s,-1)
+end
+
+mutable struct  Record
+    buffer::IOBuffer
+    tag::Tag
+    Record(b::IOBuffer,tag::Tag) = new(b,tag)
+    Record(b::IOBuffer,tag::AbstractString, pos::Int64 = -1) = new(b,Tag(tag,pos))
+    Record(b,tag::Tag) = new(IOBuffer(b),tag)
+    Record(b,tag::AbstractString,pos::Int64=-1) = new(IOBuffer(b),Tag(tag,pos))
+end
+
+mutable struct GeneratedFile
+    filename::String
+    records::Vector{Record}
+    GeneratedFile(io::String, r::Vector{Record} = Record[]) = new(io,r)
+end
+
+import Base: show
+
+function show(io::IO,gf::GeneratedFile)
+    nr = length(gf.records)
+    print(io,"GeneratedFile: $(gf.filename) with $nr records")
+end
+
+show(io::IO,r::Record) = show(io,r.tag)
+
+show(io::IO,t::Tag) = print(io,"Tag: ", t.tag," position: ", t.pos)
+
+import Base: print
+
+function Base.print(io::IO,r::Record)
+    nchar = div(r.buffer.size,sizeof(Char))
+    nchar >80
+    print(io,"Record: ",r.tag.tag,"\nText: ",String(take!(r.buffer)))
+end

src/.#types.jl

+nuccio@nuccio-Lenovo-IdeaPad-S340-15API.41142:1776683147
\ No newline at end of file

src/GeneratedFiles.jl

+module GeneratedFiles
+include("types.jl")
+include("filemanip.jl")
+
+export GeneratedFile, readGF, Record,Tag
+export GF_write, add_records!, remove_records!
+end

src/filemanip.jl

+const COMMENTCHAR = "%"
+const START_RECORD = string(COMMENTCHAR,"-start-",COMMENTCHAR)
+const END_RECORD = string(COMMENTCHAR,"-end-",COMMENTCHAR)
+const TAG_REGEX = Regex("(?<=$(START_RECORD) |$(END_RECORD) )([^\\s]+)")
+const POS_REGEX = Regex("(?<=$(START_RECORD) |$(END_RECORD) )([^\\s]+)(\\s*)(\\d+)")
+
+function seekRecord(io::IOStream)
+    while true
+        eof(io) && return false
+        startswith(io,START_RECORD) && return true
+        readline(io)
+    end
+end
+
+function findEndRecord(io::IOStream)
+    p1 = position(io)
+    p2 = -1
+    while true
+        if eof(io)
+            p2 = position(io)
+            break;
+        end
+        if startswith(io,END_RECORD)
+            readline(io)
+            p2 = position(io)
+            break;
+        end
+        readline(io)
+    end
+    return p2
+end
+
+function readRecord(io)
+    is = position(io)
+    ie = findEndRecord(io)
+    seek(io, is)
+    buffer = IOBuffer(read(io,ie-is))
+    return Record(buffer)
+end
+function readGF(filename)
+    records = Vector{Record}()
+    open(filename,"r") do io
+        while seekRecord(io)
+            push!(records,readRecord(io))
+        end
+    end
+    return GeneratedFile(filename,records)
+end
+
+function get_tag_and_pos(s::AbstractString)
+    ms = match(POS_REGEX,s)
+    isnothing(ms) && error("missing tag in Record")
+    pos = parse(Int64,match(r"[\d]+",ms.match).match)
+    tag = match(r"[^\s]+",ms.match).match
+    return tag,pos
+end
+
+function Record(b::IOBuffer)
+    tag,pos = get_tag_and_pos(readline(b))
+    is = position(b)
+    length = 0
+    for l in eachline(b)
+        if !startswith(l,END_RECORD)
+            length = position(b)-is
+            continue
+        end
+        me = match(TAG_REGEX,l)
+        isnothing(me) && error("missing tag at the end of a Record")
+        if tag != me.match
+            error("Record is malformed:\nIt start with $(ms.match)\nIt ends with $(me.match)")
+        end
+        break;
+    end
+    seek(b,is)
+    return  Record(IOBuffer(read(b,length)),tag,pos)
+end
+
+add_records!(GF::GeneratedFile,r::Record...) = push!(GF.records,r...)
+
+remove_records!(GF::GeneratedFile,tag::String) =  filter!(r->r.tag.tag != tag, GF.records)
+
+remove_records!(GF::GeneratedFile,tag::Tag) = remove_record(GF,tag.tag)
+
+function GF_write(io,r::Record)
+    println(io,START_RECORD," ",r.tag.tag," ",r.tag.pos)
+    print(io,String(take!(r.buffer)))
+    seekend(r.buffer)
+    seek(r.buffer,position(r.buffer)-1)
+    startswith(r.buffer,"\n") || print(io,"\n")
+    println(io,END_RECORD," ",r.tag.tag)
+    nothing
+end
+
+function isless_Tag(a::Tag,b::Tag)
+    a.pos == b.pos && return a.tag < b.tag
+    return a.pos<b.pos
+end
+isless_Record(a::Record,b::Record) = isless_Tag(a.tag, b.tag)
+
+function resolve_negative_pos!(R::Vector{Record})
+    any(r.tag.pos<=0 for r in R)  || return
+    maxP = max(1, maximum(R[i].tag.pos for i in eachindex(R))+1)
+
+    for (i,r) in enumerate(R)
+        r.tag.pos<=0 || continue;
+        R[i].tag.pos = maxP
+        maxP+=1
+    end
+    return
+end
+
+order_records!(R::Vector{Record}) = sort!(R,lt=isless_Record)
+
+function GF_write(GF::GeneratedFile)
+    resolve_negative_pos!(GF.records)
+    order_records!(GF.records);
+    open(GF.filename,"w") do io
+        GF_write.(io,GF.records)
+    end
+    nothing
+end

src/types.jl

+mutable struct Tag
+    tag::String
+    #=
+    Order records by position. if pos<0 they are put at the end of the list.
+    =#
+    pos::Int64 ##
+    Tag(s, pos) = new(s,pos)
+    Tag(s) = Tag(s,-1)
+end
+
+mutable struct  Record
+    buffer::IOBuffer
+    tag::Tag
+    Record(b::IOBuffer,tag::Tag) = new(b,tag)
+    Record(b::IOBuffer,tag::AbstractString, pos::Int64 = -1) = new(b,Tag(tag,pos))
+    Record(b,tag::Tag) = new(IOBuffer(b),tag)
+    Record(b,tag::AbstractString,pos::Int64=-1) = new(IOBuffer(b),Tag(tag,pos))
+end
+
+mutable struct GeneratedFile
+    filename::String
+    records::Vector{Record}
+    GeneratedFile(io::String, r::Vector{Record} = Record[]) = new(io,r)
+end
+
+import Base: show
+
+function show(io::IO,gf::GeneratedFile)
+    nr = length(gf.records)
+    print(io,"GeneratedFile: $(gf.filename) with $nr records")
+end
+
+show(io::IO,r::Record) = show(io,r.tag)
+
+show(io::IO,t::Tag) = print(io,"Tag: ", t.tag," position: ", t.pos)
+
+import Base: print
+
+function Base.print(io::IO,r::Record)
+    print(io,"Record: ",r.tag.tag,"\nText: ",String(take!(r.buffer)))
+end

test/Cinema.txt

+%-start-% film 1
+La vita è bella
+%-end-% film
+%-start-% film_d'animazione 2
+Il re Leone
+%-end-% film_d'animazione
+%-start-% TV_Show 4
+Modern Family
+%-end-% TV_Show
+%-start-% Musical 5
+The Rocky Horror Picture Show
+%-end-% Musical

test/test.jl

+using Revise, GeneratedFiles
+
+GF = GeneratedFile("Cinema.txt")
+add_records!(GF,Record("La vita è bella", "film", 1))
+add_records!(GF,Record("Il re Leone", Tag("film_d'animazione", 2)),
+             Record("The Rocky Horror Picture Show\n", "Musical"),
+             Record("Modern Family", "TV_Show", 4))
+
+GF_write(GF)
+
+GF2 = readGF("Cinema.txt")
+
+remove_records!(GF,"TV_Show")