feat: new check for valid purpose names

crates/aiken-lang/src/ast.rs

@@ -277,6 +277,15 @@ impl TypedFunction {
             })
     }
 
+    pub fn has_valid_purpose_name(&self) -> bool {
+        self.name == PURPOSE_SPEND
+            || self.name == PURPOSE_PUBLISH
+            || self.name == PURPOSE_PROPOSE
+            || self.name == PURPOSE_MINT
+            || self.name == PURPOSE_WITHDRAW
+            || self.name == PURPOSE_VOTE
+    }
+
     pub fn validator_arity(&self) -> usize {
         if self.name == PURPOSE_SPEND
             || self.name == PURPOSE_PUBLISH
@@ -628,6 +637,17 @@ pub struct Validator<T, Arg, Expr> {
 }
 
 impl TypedValidator {
+    pub fn available_purposes() -> Vec<String> {
+        vec![
+            PURPOSE_SPEND.to_string(),
+            PURPOSE_MINT.to_string(),
+            PURPOSE_WITHDRAW.to_string(),
+            PURPOSE_PUBLISH.to_string(),
+            PURPOSE_VOTE.to_string(),
+            PURPOSE_PROPOSE.to_string(),
+        ]
+    }
+
     pub fn find_node(&self, byte_index: usize) -> Option<Located<'_>> {
         self.params
             .iter()

crates/aiken-lang/src/parser/definition/snapshots/double_validator.snap

@@ -54,7 +54,7 @@ Validator(
                     name: "True",
                 },
                 doc: None,
-                location: 26..44,
+                location: 20..44,
                 name: "spend",
                 public: true,
                 return_annotation: None,
@@ -96,7 +96,7 @@ Validator(
                     name: "True",
                 },
                 doc: None,
-                location: 68..79,
+                location: 63..79,
                 name: "mint",
                 public: true,
                 return_annotation: None,

crates/aiken-lang/src/parser/definition/snapshots/fallback.snap

@@ -54,7 +54,7 @@ Validator(
                     name: "True",
                 },
                 doc: None,
-                location: 26..44,
+                location: 20..44,
                 name: "spend",
                 public: true,
                 return_annotation: None,
@@ -96,7 +96,7 @@ Validator(
                     name: "True",
                 },
                 doc: None,
-                location: 68..79,
+                location: 63..79,
                 name: "mint",
                 public: true,
                 return_annotation: None,

crates/aiken-lang/src/parser/definition/snapshots/validator.snap

@@ -54,7 +54,7 @@ Validator(
                     name: "True",
                 },
                 doc: None,
-                location: 26..44,
+                location: 20..44,
                 name: "spend",
                 public: true,
                 return_annotation: None,

crates/aiken-lang/src/parser/definition/validator.rs

@@ -23,16 +23,18 @@ pub fn parser() -> impl Parser<Token, ast::UntypedDefinition, Error = ParseError
         .then(
             select! {Token::Name {name} => name}
                 .then(args_and_body())
-                .map(|(name, mut function)| {
+                .map_with_span(|(name, mut function), span| {
                     function.name = name;
+                    function.location.start = span.start;
 
                     function
                 })
                 .repeated()
                 .then(
                     just(Token::Else)
-                        .ignore_then(args_and_body().map(|mut function| {
+                        .ignore_then(args_and_body().map_with_span(|mut function, span| {
                             function.name = "else".to_string();
+                            function.location.start = span.start;
 
                             function
                         }))

crates/aiken-lang/src/tipo/error.rs

@@ -8,6 +8,7 @@ use crate::{
     pretty::Documentable,
 };
 use indoc::formatdoc;
+use itertools::Itertools;
 use miette::{Diagnostic, LabeledSpan};
 use ordinal::Ordinal;
 use owo_colors::{
@@ -1070,6 +1071,21 @@ The best thing to do from here is to remove it."#))]
         function: UntypedFunction,
         location: Span,
     },
+
+    #[error("I found a validator handler referring to an unknown purpose.\n")]
+    #[diagnostic(code("unknown::purpose"))]
+    #[diagnostic(help(
+        "Handler must be named after a known purpose. Here is a list of available purposes:\n{}",
+        available_purposes
+          .iter()
+          .map(|p| format!("-> {}", p.if_supports_color(Stdout, |s| s.green())))
+          .join("\n")
+    ))]
+    UnknownPurpose {
+        #[label("unknown purpose")]
+        location: Span,
+        available_purposes: Vec<String>,
+    },
 }
 
 impl ExtraData for Error {
@@ -1129,6 +1145,7 @@ impl ExtraData for Error {
             | Error::UnexpectedMultiPatternAssignment { .. }
             | Error::ExpectOnOpaqueType { .. }
             | Error::ValidatorMustReturnBool { .. }
+            | Error::UnknownPurpose { .. }
             | Error::MustInferFirst { .. } => None,
 
             Error::UnknownType { name, .. }

crates/aiken-lang/src/tipo/infer.rs

@@ -9,7 +9,7 @@ use crate::{
     ast::{
         Annotation, ArgName, ArgVia, DataType, Definition, Function, ModuleConstant, ModuleKind,
         RecordConstructor, RecordConstructorArg, Tracing, TypeAlias, TypedArg, TypedDefinition,
-        TypedModule, UntypedArg, UntypedDefinition, UntypedModule, Use, Validator,
+        TypedModule, TypedValidator, UntypedArg, UntypedDefinition, UntypedModule, Use, Validator,
     },
     builtins::{self, fuzzer, generic_var},
     tipo::{expr::infer_function, Span, Type, TypeVar},
@@ -209,7 +209,15 @@ fn infer_definition(
 
                         typed_fun.arguments.drain(0..params_length);
 
-                        // TODO: the expected number of args comes from the script purpose
+                        if !typed_fun.has_valid_purpose_name() {
+                            return Err(Error::UnknownPurpose {
+                                location: typed_fun
+                                    .location
+                                    .map(|start, _end| (start, start + typed_fun.name.len())),
+                                available_purposes: TypedValidator::available_purposes(),
+                            });
+                        }
+
                         if typed_fun.arguments.len() != typed_fun.validator_arity() {
                             return Err(Error::IncorrectValidatorArity {
                                 count: typed_fun.arguments.len() as u32,

crates/aiken-project/src/blueprint/snapshots/aiken_project__blueprint__validator__tests__mint_basic.snap

@@ -1,9 +1,9 @@
 ---
 source: crates/aiken-project/src/blueprint/validator.rs
-description: "Code:\n\nvalidator {\n  fn mint(redeemer: Data, ctx: Data) {\n    True\n  }\n}\n// "
+description: "Code:\n\nvalidator thing {\n  mint(redeemer: Data, policy_id: Data, transaction: Data) {\n    True\n  }\n}\n// "
 ---
 {
-  "title": "test_module.mint",
+  "title": "test_module.thing_mint",
   "redeemer": {
     "title": "redeemer",
     "schema": {

crates/aiken-project/src/blueprint/snapshots/aiken_project__blueprint__validator__tests__opaque_singleton_multi_variants.snap

@@ -1,6 +1,6 @@
 ---
 source: crates/aiken-project/src/blueprint/validator.rs
-description: "Code:\n\npub opaque type Rational {\n  numerator: Int,\n  denominator: Int,\n}\n\nvalidator {\n  fn opaque_singleton_multi_variants(redeemer: Rational, ctx: Void) {\n    True\n  }\n}\n"
+description: "Code:\n\npub opaque type Rational {\n  numerator: Int,\n  denominator: Int,\n}\n\nvalidator opaque_singleton_multi_variants {\n  spend(redeemer: Rational, oref: Data, ctx: Void) {\n    True\n  }\n}\n"
 ---
 Schema {
     error: Error {
@@ -16,7 +16,7 @@ Schema {
             },
         ],
     },
-    location: 117..135,
+    location: 120..138,
     source_code: NamedSource {
         name: "",
         source: "<redacted>",