Implement generator for impl Default

[SamuelMarks]

No description provided.

[SamuelMarks]

@Wulf Something weird is happening on my latest commit:

if update_struct.has_code() {
    ret_buffer.push('\n');
    ret_buffer.push_str(update_struct.code());
    if config.options.default_impl {
        ret_buffer.push('\n');
        ret_buffer.push_str(
            build_default_impl_fn(
                &format!("Update{struct_name}"),
                &update_struct.table.columns,
            )
            .as_str(),
        );
    }
    ret_buffer.push('\n');
}

The update_struct.table.columns has column names which are only present in the other structs; but not the update one. Which table should I use?

[hasezoey]

Please add tests (see simple_table_sqlite as a example), aside from that some minor style improvements.

[hasezoey]

btw, we dont have a CONTRIBUTING currently, but the commit style is angular/conventional-ish, see the commit history for examples.

[SamuelMarks]

Good suggestions. Yeah I still need to add tests, but it should be ready now (aside from that).

[hasezoey]

Looks better, but still the tests are missing (at least one for being enabled with most common types).

Also consider using r# and multiple lines instead of \n for the format! (like other code in the file), example:

dsync/src/code.rs

Lines 497 to 515 in 2797966

	r##"
	/// Insert a new row into `{table_name}` with a given [`{create_struct_identifier}`]
	pub{async_keyword} fn create(db: &mut ConnectionType, item: &{create_struct_identifier}) -> diesel::QueryResult<Self> {{
	use {schema_path}{table_name}::dsl::*;
	diesel::insert_into({table_name}).values(item).get_result::<Self>(db){await_keyword}
	}}
	"##
	));
	} else {
	buffer.push_str(&format!(
	r##"
	/// Insert a new row into `{table_name}` with all default values
	pub{async_keyword} fn create(db: &mut ConnectionType) -> diesel::QueryResult<Self> {{
	use {schema_path}{table_name}::dsl::*;
	diesel::insert_into({table_name}).default_values().get_result::<Self>(db){await_keyword}
	}}
	"##

PS: also existing test output needs to be updated if it is meant to change. (though to my understanding it shouldnt change as long as default_impl is false, which it is by default)

[hasezoey]

Suggested change

	struct_name = struct_name, f2d=fields_to_defaults.as_str()
	f2d=fields_to_defaults.as_str()

unless i missed something, that shouldnt be required anymore.

i think f2d should also be able to be directly embedded.