Pre/Post Scripts

In cargo-generate.toml write a [hooks] section, example:

[template]
cargo_generate_version = "0.10.0"

[hooks]
pre = ["pre-script.rhai"]
#post = [...]

[placeholders]
license = { type = "string", prompt = "What license to use?", choices = ["APACHE", "MIT"], default = "MIT" }

Now, write the script in Rhai, utilizing the cargo-generate provided extensions:

// we can see existing variables.
// note that template and Rhai variables are separate!
let crate_type = variable::get("crate_type")
debug(`crate_type: ${crate_type}`);

let license = variable::get("license").to_upper();
while switch license {
  "APACHE" => {
    file::delete("LICENSE-MIT");
    file::rename("LICENSE-APACHE", "LICENSE");
    false
  }
  "MIT" => {
    file::delete("LICENSE-APACHE");
    file::rename("LICENSE-MIT", "LICENSE");
    false
  }
  _ => true,
} {
  license = variable::prompt("Select license?", "MIT", [
    "APACHE",
    "MIT",
  ]);
}
variable::set("license", license);

Rhai extensions

Besides the basic Rhai features, these are the modules/behaviors defined:

Variables

get/set

variable::is_set(name: &str) -> bool

Returns true if the variable/placeholder has been set for the template
variable::get(name: &str) -> value

Gets any defined variable in the Liquid template object
variable::set(name: &str, value: (&str|bool))

Set new or overwrite existing variables. Do not allow to change types.

Prompt

variable::prompt(text: &str, default_value: bool) -> value

Prompt the user for a boolean value
variable::prompt(text: &str) -> value

Prompt the user for a string value
variable::prompt(text: &str, default_value: &str) -> value

Prompt the user for a string value, with a default already in place
variable::prompt(text: &str, default_value: &str, regex: &str) -> value

Prompt the user for a string value, validated with a regex
variable::prompt(text: &str, default_value: &str, choices: Array) -> value

Prompt the user for a choice value

Files

file::rename(from: &str, to: &str)

Rename one of the files in the template folder
file::delete(path: &str)

Delete a file or folder inside the template folder
file::write(file: &str, content: &str)

Create/overwrite a file inside the template folder
*file::write(file: &str, content: Array)

Create/overwrite a file inside the template folder, each entry in the array on a new line

Other

abort(reason: &str): Aborts cargo-generate with a script error.

Changing case of strings

to_kebab_case(str: &str) -> String

"We are going to inherit the earth." => "we-are-going-to-inherit-the-earth"
to_lower_camel_case(str: &str) -> String

"It is we who built these palaces and cities." => "itIsWeWhoBuiltThesePalacesAndCities"
to_pascal_case(str: &str) -> String

Same as to_upper_camel_case(str: &str) -> String
to_shouty_kebab_case(str: &str) -> String

"We are going to inherit the earth." => "WE-ARE-GOING-TO-INHERIT-THE-EARTH"
to_shouty_snake_case(str: &str) -> String

"That world is growing in this minute." => "THAT_WORLD_IS_GROWING_IN_THIS_MINUTE"
to_snake_case(str: &str) -> String

"We carry a new world here, in our hearts." => "we_carry_a_new_world_here_in_our_hearts"
to_title_case(str: &str) -> String

"We have always lived in slums and holes in the wall." => "We Have Always Lived In Slums And Holes In The Wall"
to_upper_camel_case(str: &str) -> String

"We are not in the least afraid of ruins." => "WeAreNotInTheLeastAfraidOfRuins"

Cargo Generate Documentation