repl: open file as read and append to cmds before open as write

closes #7
This commit is contained in:
Luna 2019-10-06 14:39:15 -03:00
parent cb689c3ade
commit 66b262beb2

View file

@ -28,12 +28,6 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
const scri_path = try (args_it.next(allocator) orelse @panic("expected scri path"));
var file = try std.fs.File.openWrite(scri_path);
defer file.close();
var out = file.outStream();
var stream = &out.stream;
// the thing here is that 'load :0' would load the scri_path, since we
// now have a 'repl' argument right before it. to counteract that, the
// initial repl buffer contains 'load :1' instead.
@ -49,6 +43,37 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
defer cmds.deinit();
// if the scri file already had commands, we add them up on the cmd list
var file_read = try std.fs.openReead(scri_path);
const total_bytes = try file_read.getEndPos();
if (total_bytes > 0) {
var scri_existing = try allocator.alloc(u8, total_bytes);
defer allocator.free(scri_existing);
_ = try file.read(slice);
file_read.close();
var existing_cmds = try lang.parse(scri_existing);
defer existing_cmds.deinit();
// copy the existing command list into the repl's command list
var it = existing_cmds.iterator();
while (it.next()) |existing_cmd| {
try cmds.append(existing_cmd);
}
}
var file = try std.fs.File.openWrite(scri_path);
defer file.close();
var out = file.outStream();
var stream = &out.stream;
// since we opened the file for writing, it becomes empty, so, to ensure
// we don't fuck up later on, we print cmds before starting the repl
try printer.printList(cmds, stream);
// we keep
// - a CommandList with the full commands we have right now
// - a Command with the current last typed successful command
@ -99,6 +124,8 @@ pub fn doRepl(allocator: *std.mem.Allocator, args_it: var) !void {
try printer.printList(cmds, stdout);
continue;
} else if (std.mem.eql(u8, line, "save")) {
// seek to 0 instead of appending the new command
// NOTE appending single command might be faster
try file.seekTo(0);
try printer.printList(cmds, stream);
continue;