suggest similarly named functions if invoked function does not exist

Cargo.toml

@@ -27,10 +27,12 @@ colored = "2.1.0"
 derive_more = { version = "0.99.17", default-features = false, features = ["deref", "from", "deref_mut"] }
 enum-as-inner = "0.6.0"
 getset = "0.1.2"
+itertools = "0.13.0"
 mlua = { version = "0.9.7", features = ["lua54", "vendored"], optional = true }
 path-absolutize = "3.1.1"
 serde = { version = "1.0.197", features = ["derive", "rc"], optional = true }
 shulkerbox = { git = "https://github.com/moritz-hoelting/shulkerbox", default-features = false, optional = true, rev = "a2d20dab8ea97bbd873edafb23afaad34292457f" }
+strsim = "0.11.1"
 strum = { version = "0.26.2", features = ["derive"] }
 strum_macros = "0.26.2"
 thiserror = "1.0.58"

src/lib.rs

@@ -29,6 +29,9 @@ use shulkerbox::{datapack::Datapack, virtual_fs::VFolder};
 
 use crate::lexical::token_stream::TokenStream;
 
+/// The version of the `ShulkerScript` language.
+pub const VERSION: &str = env!("CARGO_PKG_VERSION");
+
 /// Converts the given source code to tokens and returns a token stream.
 ///
 /// # Errors

src/transpile/error.rs

@@ -1,6 +1,9 @@
 //! Errors that can occur during transpilation.
 
-use std::fmt::Display;
+use std::{collections::HashMap, fmt::Display};
+
+use getset::Getters;
+use itertools::Itertools;
 
 use crate::{
     base::{
@@ -10,6 +13,8 @@ use crate::{
     syntax::syntax_tree::expression::Expression,
 };
 
+use super::transpiler::FunctionData;
+
 /// Errors that can occur during transpilation.
 #[allow(clippy::module_name_repetitions, missing_docs)]
 #[derive(Debug, thiserror::Error, Clone)]
@@ -28,9 +33,41 @@ pub enum TranspileError {
 pub type TranspileResult<T> = Result<T, TranspileError>;
 
 /// An error that occurs when a function declaration is missing.
-#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Getters)]
 pub struct MissingFunctionDeclaration {
-    pub span: Span,
+    #[get = "pub"]
+    span: Span,
+    #[get = "pub"]
+    alternatives: Vec<FunctionData>,
+}
+
+impl MissingFunctionDeclaration {
+    pub(super) fn from_context(
+        identifier_span: Span,
+        functions: &HashMap<(String, String), FunctionData>,
+    ) -> Self {
+        let own_name = identifier_span.str();
+        let own_program_identifier = identifier_span.source_file().identifier();
+        let alternatives = functions
+            .iter()
+            .filter_map(|((program_identifier, function_name), data)| {
+                let normalized_distance = strsim::normalized_levenshtein(own_name, function_name);
+                (program_identifier == own_program_identifier
+                    && (normalized_distance > 0.8
+                        || strsim::levenshtein(own_name, function_name) < 3))
+                    .then_some((normalized_distance, data))
+            })
+            .sorted_by(|a, b| a.0.partial_cmp(&b.0).unwrap_or(std::cmp::Ordering::Equal))
+            .map(|(_, data)| data)
+            .take(8)
+            .cloned()
+            .collect::<Vec<_>>();
+
+        Self {
+            alternatives,
+            span: identifier_span,
+        }
+    }
 }
 
 impl Display for MissingFunctionDeclaration {
@@ -41,10 +78,23 @@ impl Display for MissingFunctionDeclaration {
         );
         write!(f, "{}", Message::new(Severity::Error, message))?;
 
+        let help_message = if self.alternatives.is_empty() {
+            None
+        } else {
+            let mut message = String::from("did you mean ");
+            for (i, alternative) in self.alternatives.iter().enumerate() {
+                if i > 0 {
+                    message.push_str(", ");
+                }
+                message.push_str(&format!("`{}`", alternative.identifier_span.str()));
+            }
+            Some(message + "?")
+        };
+
         write!(
             f,
             "\n{}",
-            SourceCodeDisplay::new(&self.span, Option::<u8>::None)
+            SourceCodeDisplay::new(&self.span, help_message.as_ref())
         )
     }
 }

src/transpile/transpiler.rs

@@ -35,13 +35,13 @@ pub struct Transpiler {
     aliases: RwLock<HashMap<(String, String), (String, String)>>,
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
-struct FunctionData {
+pub(super) struct FunctionData {
-    namespace: String,
+    pub(super) namespace: String,
-    identifier_span: Span,
+    pub(super) identifier_span: Span,
-    statements: Vec<Statement>,
+    pub(super) statements: Vec<Statement>,
-    public: bool,
+    pub(super) public: bool,
-    annotations: HashMap<String, Option<String>>,
+    pub(super) annotations: HashMap<String, Option<String>>,
 }
 
 impl Transpiler {
@@ -224,9 +224,10 @@ impl Transpiler {
                     })
                     .ok_or_else(|| {
                         let error = TranspileError::MissingFunctionDeclaration(
-                            MissingFunctionDeclaration {
+                            MissingFunctionDeclaration::from_context(
-                                span: identifier_span.clone(),
+                                identifier_span.clone(),
-                            },
+                                &functions,
+                            ),
                         );
                         handler.receive(error.clone());
                         error
@@ -244,10 +245,12 @@ impl Transpiler {
                         .and_then(|q| functions.get(&q).filter(|f| f.public))
                 })
                 .ok_or_else(|| {
-                    let error =
+                    let error = TranspileError::MissingFunctionDeclaration(
-                        TranspileError::MissingFunctionDeclaration(MissingFunctionDeclaration {
+                        MissingFunctionDeclaration::from_context(
-                            span: identifier_span.clone(),
+                            identifier_span.clone(),
-                        });
+                            &functions,
+                        ),
+                    );
                     handler.receive(error.clone());
                     error
                 })?;
@@ -297,10 +300,12 @@ impl Transpiler {
             .get(&program_query)
             .or_else(|| alias_query.and_then(|q| locations.get(&q).filter(|(_, p)| *p)))
             .ok_or_else(|| {
-                let error =
+                let error = TranspileError::MissingFunctionDeclaration(
-                    TranspileError::MissingFunctionDeclaration(MissingFunctionDeclaration {
+                    MissingFunctionDeclaration::from_context(
-                        span: identifier_span.clone(),
+                        identifier_span.clone(),
-                    });
+                        &self.functions.read().unwrap(),
+                    ),
+                );
                 handler.receive(error.clone());
                 error
             })