Remove 'purpose' from blueprint's schema.

This has been removed from the CIP-0057 specification since validators
  are often re-used for multiple purposes (especially validators with
  arity 2). It's misleading to assign a validator a purpose since the
  purpose distinction actually happens _within_ the validator itself.

crates/aiken-lang/src/lib.rs

@@ -30,11 +30,5 @@ impl IdGenerator {
     }
 }
 
-pub const SPEND: &str = "spend";
-pub const PUBLISH: &str = "publish";
-pub const MINT: &str = "mint";
-pub const WITHDRAW: &str = "withdraw";
-pub const VALIDATOR_NAMES: [&str; 4] = [SPEND, PUBLISH, MINT, WITHDRAW];
-
 #[cfg(test)]
 mod tests;

crates/aiken-project/src/blueprint/validator.rs

@@ -16,8 +16,6 @@ use uplc::ast::{DeBruijn, Program, Term};
 pub struct Validator<T> {
     pub title: String,
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub purpose: Option<Purpose>,
-    #[serde(skip_serializing_if = "Option::is_none")]
     pub description: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub datum: Option<Annotated<T>>,
@@ -29,15 +27,6 @@ pub struct Validator<T> {
     pub program: Program<DeBruijn>,
 }
 
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, serde::Serialize, serde::Deserialize)]
-#[serde(rename_all = "camelCase")]
-pub enum Purpose {
-    Spend,
-    Mint,
-    Withdraw,
-    Publish,
-}
-
 impl Display for Validator<Schema> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let s = serde_json::to_string_pretty(self).map_err(|_| fmt::Error)?;
@@ -63,7 +52,6 @@ impl Validator<Schema> {
         Ok(Validator {
             title: format!("{}.{}", &module.name, &def.fun.name),
             description: None,
-            purpose: None,
             parameters: def
                 .params
                 .iter()
@@ -137,40 +125,6 @@ where
     }
 }
 
-impl Purpose {
-    pub fn min_arity(&self) -> u8 {
-        match self {
-            Purpose::Spend => 3,
-            Purpose::Mint | Purpose::Withdraw | Purpose::Publish => 2,
-        }
-    }
-}
-
-impl Display for Purpose {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        f.write_str(match self {
-            Purpose::Spend => "spend",
-            Purpose::Mint => "mint",
-            Purpose::Withdraw => "withdraw",
-            Purpose::Publish => "publish",
-        })
-    }
-}
-
-impl TryFrom<String> for Purpose {
-    type Error = String;
-
-    fn try_from(purpose: String) -> Result<Purpose, Self::Error> {
-        match &purpose[..] {
-            "spend" => Ok(Purpose::Spend),
-            "mint" => Ok(Purpose::Mint),
-            "withdraw" => Ok(Purpose::Withdraw),
-            "publish" => Ok(Purpose::Publish),
-            unexpected => Err(format!("Can't turn '{unexpected}' into any Purpose")),
-        }
-    }
-}
-
 #[cfg(test)]
 mod test {
     use super::*;

crates/aiken-project/src/lib.rs

@@ -399,8 +399,7 @@ where
             .into_iter()
             .map(|validator| {
                 let same_title = validator.title == applied_validator.title;
-                let same_purpose = validator.purpose == applied_validator.purpose;
-                if same_title && same_purpose {
+                if same_title {
                     applied_validator.to_owned()
                 } else {
                     validator