1 files changed, 108 insertions, 0 deletions

diff --git a/src/eval/analysis.rs b/src/eval/analysis.rs
new file mode 100644
index 0000000..b3a0083
--- /dev/null
+++ b/src/eval/analysis.rs
@@ -0,0 +1,108 @@
+use crate::{ast, Wrap};
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Analysis {
+    diagnostics: Vec<Diagnostic>,
+}
+
+impl Analysis {
+    pub fn print(&self) {
+        for Diagnostic { level, kind } in &self.diagnostics {
+            eprintln!("{level} {kind}");
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Diagnostic {
+    level: Level,
+    kind: Kind,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Level {
+    Warning,
+    Error,
+}
+
+impl std::fmt::Display for Level {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Level::Warning => write!(f, "[warning]"),
+            Level::Error => write!(f, "[error]"),
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Kind {
+    Pattern {
+        invalid_node_kind: String,
+        full_pattern: ast::Pattern,
+    },
+}
+
+impl std::fmt::Display for Kind {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::Pattern {
+                invalid_node_kind,
+                full_pattern,
+            } => {
+                write!(
+                    f,
+                    "invalid node kind `{invalid_node_kind}` in pattern `{full_pattern}`"
+                )
+            }
+        }
+    }
+}
+
+pub fn run(ctx: &super::Context) -> Analysis {
+    [validate_patterns(ctx)]
+        .into_iter()
+        .flatten()
+        .collect::<Vec<_>>()
+        .wrap(|diagnostics| Analysis { diagnostics })
+}
+
+fn validate_patterns(ctx: &super::Context) -> Vec<Diagnostic> {
+    fn validate_pattern(
+        pattern: &ast::TreePattern,
+        language: &tree_sitter::Language,
+    ) -> Option<String> {
+        match pattern {
+            ast::TreePattern::Atom(a) => {
+                if language.id_for_node_kind(a, true) == 0 {
+                    Some(a.to_owned())
+                } else {
+                    None
+                }
+            }
+            ast::TreePattern::List(items) => {
+                for item in items {
+                    validate_pattern(item, language)?;
+                }
+                None
+            }
+        }
+    }
+
+    ctx.program
+        .stanzas
+        .iter()
+        .flat_map(|s| match &s.pattern {
+            ast::Pattern::Begin | ast::Pattern::End => None,
+            ast::Pattern::Tree { matcher, .. } => {
+                validate_pattern(matcher, &ctx.language).map(|invalid_node_kind| Kind::Pattern {
+                    invalid_node_kind,
+                    full_pattern: s.pattern.clone(),
+                })
+            }
+        })
+        .map(|kind| Diagnostic {
+            level: Level::Error,
+            kind,
+        })
+        .collect()
+}