Add did you mean question to wrong variables

Cargo.lock

@@ -1114,6 +1114,12 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
+[[package]]
+name = "levenshtein"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db13adb97ab515a3691f56e4dbab09283d0b86cb45abd991d8634a9d6f501760"
+
 [[package]]
 name = "libc"
 version = "0.2.98"
@@ -1890,6 +1896,7 @@ dependencies = [
  "itertools 0.10.1",
  "lalrpop",
  "lalrpop-util",
+ "levenshtein",
  "logos",
  "maplit",
  "once_cell",

crates/simplexpr/Cargo.toml

@@ -18,6 +18,7 @@ logos = "0.12"
 once_cell = "1.8.0"
 serde = {version = "1.0", features = ["derive"]}
 serde_json = "1.0"
+levenshtein = "1.0"
 
 strum = { version = "0.21", features = ["derive"] }
 

crates/simplexpr/src/eval.rs

@@ -16,7 +16,7 @@ pub enum EvalError {
     InvalidRegex(#[from] regex::Error),
 
     #[error("Unknown variable {0}")]
-    UnknownVariable(VarName),
+    UnknownVariable(VarName, Vec<VarName>),
 
     #[error(transparent)]
     ConversionError(#[from] ConversionError),
@@ -108,7 +108,11 @@ impl SimplExpr {
             )),
             VarRef(span, ref name) => match variables.get(name) {
                 Some(value) => Ok(Literal(value.clone())),
-                None => Err(EvalError::UnknownVariable(name.clone()).at(span)),
+                None => {
+                    let similar_ish =
+                        variables.keys().filter(|key| levenshtein::levenshtein(&key.0, &name.0) < 3).cloned().collect_vec();
+                    Err(EvalError::UnknownVariable(name.clone(), similar_ish).at(span))
+                }
             },
         }
     }
@@ -138,7 +142,7 @@ impl SimplExpr {
         match self.eval(&HashMap::new()) {
             Ok(x) => Ok(x),
             Err(x) => Err(x.map_in_span(|err| match err {
-                EvalError::UnknownVariable(name) => EvalError::NoVariablesAllowed(name),
+                EvalError::UnknownVariable(name, _) => EvalError::NoVariablesAllowed(name),
                 other => other,
             })),
         }
@@ -149,7 +153,13 @@ impl SimplExpr {
         let value = match self {
             SimplExpr::Literal(x) => Ok(x.clone()),
             SimplExpr::VarRef(span, ref name) => {
-                Ok(values.get(name).cloned().ok_or_else(|| EvalError::UnknownVariable(name.clone()).at(*span))?.at(*span))
+                let similar_ish =
+                    values.keys().filter(|keys| levenshtein::levenshtein(&keys.0, &name.0) < 3).cloned().collect_vec();
+                Ok(values
+                    .get(name)
+                    .cloned()
+                    .ok_or_else(|| EvalError::UnknownVariable(name.clone(), similar_ish).at(*span))?
+                    .at(*span))
             }
             SimplExpr::BinOp(_, a, op, b) => {
                 let a = a.eval(values)?;

crates/yuck/Cargo.toml

@@ -30,10 +30,10 @@ strum = { version = "0.21", features = ["derive"] }
 anyhow = "1"
 static_assertions = "1.1"
 
-
 simplexpr = { path = "../simplexpr" }
 eww_shared_util = { path = "../eww_shared_util" }
 
+
 [build-dependencies]
 lalrpop = "0.19.5"
 

crates/yuck/src/config/backend_window_options.rs

@@ -92,9 +92,7 @@ mod backend {
     }
 
     impl FromAstElementContent for StrutDefinition {
-        fn get_element_name() -> &'static str {
+        const ELEMENT_NAME: &'static str = "struts";
-            "struts"
-        }
 
         fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
             let mut attrs = iter.expect_key_values()?;

crates/yuck/src/config/config.rs

@@ -25,6 +25,15 @@ use crate::{
 };
 use eww_shared_util::{AttrName, Span, VarName};
 
+pub static TOP_LEVEL_DEFINITION_NAMES: &[&str] = &[
+    WidgetDefinition::ELEMENT_NAME,
+    WindowDefinition::ELEMENT_NAME,
+    VarDefinition::ELEMENT_NAME,
+    ListenScriptVar::ELEMENT_NAME,
+    PollScriptVar::ELEMENT_NAME,
+    Include::ELEMENT_NAME,
+];
+
 #[derive(Debug, PartialEq, Eq, Clone, serde::Serialize)]
 pub struct Include {
     pub path: String,
@@ -32,9 +41,7 @@ pub struct Include {
 }
 
 impl FromAstElementContent for Include {
-    fn get_element_name() -> &'static str {
+    const ELEMENT_NAME: &'static str = "include";
-        "include"
-    }
 
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
         let (path_span, path) = iter.expect_literal()?;
@@ -57,16 +64,16 @@ impl FromAst for TopLevel {
         let mut iter = e.try_ast_iter()?;
         let (sym_span, element_name) = iter.expect_symbol()?;
         Ok(match element_name.as_str() {
-            x if x == Include::get_element_name() => Self::Include(Include::from_tail(span, iter)?),
+            x if x == Include::ELEMENT_NAME => Self::Include(Include::from_tail(span, iter)?),
-            x if x == WidgetDefinition::get_element_name() => Self::WidgetDefinition(WidgetDefinition::from_tail(span, iter)?),
+            x if x == WidgetDefinition::ELEMENT_NAME => Self::WidgetDefinition(WidgetDefinition::from_tail(span, iter)?),
-            x if x == VarDefinition::get_element_name() => Self::VarDefinition(VarDefinition::from_tail(span, iter)?),
+            x if x == VarDefinition::ELEMENT_NAME => Self::VarDefinition(VarDefinition::from_tail(span, iter)?),
-            x if x == PollScriptVar::get_element_name() => {
+            x if x == PollScriptVar::ELEMENT_NAME => {
                 Self::ScriptVarDefinition(ScriptVarDefinition::Poll(PollScriptVar::from_tail(span, iter)?))
             }
-            x if x == ListenScriptVar::get_element_name() => {
+            x if x == ListenScriptVar::ELEMENT_NAME => {
                 Self::ScriptVarDefinition(ScriptVarDefinition::Listen(ListenScriptVar::from_tail(span, iter)?))
             }
-            x if x == WindowDefinition::get_element_name() => Self::WindowDefinition(WindowDefinition::from_tail(span, iter)?),
+            x if x == WindowDefinition::ELEMENT_NAME => Self::WindowDefinition(WindowDefinition::from_tail(span, iter)?),
             x => return Err(AstError::UnknownToplevel(sym_span, x.to_string())),
         })
     }

crates/yuck/src/config/script_var_definition.rs

@@ -61,9 +61,7 @@ pub struct PollScriptVar {
 }
 
 impl FromAstElementContent for PollScriptVar {
-    fn get_element_name() -> &'static str {
+    const ELEMENT_NAME: &'static str = "defpoll";
-        "defpoll"
-    }
 
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
         let result: AstResult<_> = try {
@@ -91,9 +89,7 @@ pub struct ListenScriptVar {
     pub name_span: Span,
 }
 impl FromAstElementContent for ListenScriptVar {
-    fn get_element_name() -> &'static str {
+    const ELEMENT_NAME: &'static str = "deflisten";
-        "deflisten"
-    }
 
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
         let result: AstResult<_> = try {

crates/yuck/src/config/var_definition.rs

@@ -2,11 +2,14 @@ use std::collections::HashMap;
 
 use simplexpr::{dynval::DynVal, SimplExpr};
 
-use crate::{error::{AstResult, AstResultExt}, parser::{
+use crate::{
+    error::{AstResult, AstResultExt},
+    parser::{
         ast::Ast,
         ast_iterator::AstIterator,
         from_ast::{FromAst, FromAstElementContent},
-    }};
+    },
+};
 use eww_shared_util::{AttrName, Span, VarName};
 
 #[derive(Debug, PartialEq, Eq, Clone, serde::Serialize)]
@@ -17,9 +20,7 @@ pub struct VarDefinition {
 }
 
 impl FromAstElementContent for VarDefinition {
-    fn get_element_name() -> &'static str {
+    const ELEMENT_NAME: &'static str = "defvar";
-        "defvar"
-    }
 
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
         let result: AstResult<_> = try {

crates/yuck/src/config/widget_definition.rs

@@ -23,9 +23,7 @@ pub struct WidgetDefinition {
 }
 
 impl FromAstElementContent for WidgetDefinition {
-    fn get_element_name() -> &'static str {
+    const ELEMENT_NAME: &'static str = "defwidget";
-        "defwidget"
-    }
 
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
         let (_, name) = iter.expect_symbol()?;

crates/yuck/src/config/window_definition.rs

@@ -27,9 +27,7 @@ pub struct WindowDefinition {
 }
 
 impl FromAstElementContent for WindowDefinition {
-    fn get_element_name() -> &'static str {
+    const ELEMENT_NAME: &'static str = "defwindow";
-        "defwindow"
-    }
 
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
         let (_, name) = iter.expect_symbol()?;

crates/yuck/src/config/window_geometry.rs

@@ -117,9 +117,7 @@ pub struct WindowGeometry {
 }
 
 impl FromAstElementContent for WindowGeometry {
-    fn get_element_name() -> &'static str {
+    const ELEMENT_NAME: &'static str = "geometry";
-        "geometry"
-    }
 
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, mut iter: AstIterator<I>) -> AstResult<Self> {
         let mut attrs = iter.expect_key_values()?;

crates/yuck/src/format_diagnostic.rs

@@ -1,10 +1,12 @@
 use codespan_reporting::{diagnostic, files};
+use config::TOP_LEVEL_DEFINITION_NAMES;
+use itertools::Itertools;
 use simplexpr::dynval;
 
 use diagnostic::*;
 
 use crate::{
-    config::{attributes::AttrError, validate::ValidationError},
+    config::{attributes::AttrError, config, validate::ValidationError},
     error::{get_parse_error_span, AstError},
 };
 
@@ -75,12 +77,15 @@ impl ToDiagnostic for Diagnostic<usize> {
 impl ToDiagnostic for AstError {
     fn to_diagnostic(&self) -> Diagnostic<usize> {
         match self {
-            AstError::UnknownToplevel(span, name) => gen_diagnostic!(self, span),
+            AstError::UnknownToplevel(span, name) => gen_diagnostic! {
+                msg = self,
+                label = span,
+                note = format!("Must be one of: {}", TOP_LEVEL_DEFINITION_NAMES.iter().join(", "))
+            },
             AstError::MissingNode(span) => gen_diagnostic! {
                 msg = "Expected another element",
                 label = span => "Expected another element here",
             },
-
             AstError::WrongExprType(span, expected, actual) => gen_diagnostic! {
                 msg = "Wrong type of expression",
                 label = span => format!("Expected a `{}` here", expected),
@@ -207,12 +212,18 @@ impl ToDiagnostic for simplexpr::eval::EvalError {
         use simplexpr::eval::EvalError::*;
         match self {
             NoVariablesAllowed(name) => gen_diagnostic!(self),
+            UnknownVariable(name, similar) => {
+                let mut notes = Vec::new();
+                if similar.len() == 1 {
+                    notes.push(format!("Did you mean `{}`?", similar.first().unwrap()))
+                } else if similar.len() > 1 {
+                    notes.push(format!("Did you mean one of: {}?", similar.iter().map(|x| format!("`{}`", x)).join(", ")))
+                }
                 // TODO the note here is confusing when it's an unknown variable being used _within_ a string literal / simplexpr
                 // it only really makes sense on top-level symbols
-            UnknownVariable(name) => gen_diagnostic! {
+                notes.push(format!("If you meant to use the literal value \"{}\", surround the value in quotes", name));
-                msg = self,
+                gen_diagnostic!(self).with_notes(notes)
-                note = format!("If you meant to use the literal value \"{}\", surround the value in quotes", name)
+            }
-            },
             Spanned(span, error) => error.as_ref().to_diagnostic().with_label(span_to_primary_label(*span)),
             _ => gen_diagnostic!(self, self.span()),
         }

crates/yuck/src/parser/from_ast.rs

@@ -31,7 +31,7 @@ impl FromAst for String {
 /// A trait that allows creating a type from the tail of a list-node.
 /// I.e. to parse (foo [a b] (c d)), [from_tail] would just get [a b] (c d).
 pub trait FromAstElementContent: Sized {
-    fn get_element_name() -> &'static str;
+    const ELEMENT_NAME: &'static str;
     fn from_tail<I: Iterator<Item = Ast>>(span: Span, iter: AstIterator<I>) -> AstResult<Self>;
 }
 
@@ -40,8 +40,8 @@ impl<T: FromAstElementContent> FromAst for T {
         let span = e.span();
         let mut iter = e.try_ast_iter()?;
         let (element_name_span, element_name) = iter.expect_symbol()?;
-        if Self::get_element_name() != element_name {
+        if Self::ELEMENT_NAME != element_name {
-            return Err(AstError::MismatchedElementName(element_name_span, Self::get_element_name().to_string(), element_name));
+            return Err(AstError::MismatchedElementName(element_name_span, Self::ELEMENT_NAME.to_string(), element_name));
         }
         Self::from_tail(span, iter)
     }