Merge pull request #135 from tree-sitter/inherited-scoped-variables

Inherited scoped variables

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## v0.10.3 -- 2023-06-01
+
+### DSL
+
+#### Added
+
+- Scoped variables can be inherited by child nodes by specifying `inherit .var_name` as part of the source. Using `@node.var_name` will either use the value set on the node itself, or otherwise the one set on the closest enclosing node.
+
 ## v0.10.2 -- 2023-05-25
 
 ### Library

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tree-sitter-graph"
-version = "0.10.2"
+version = "0.10.3"
 description = "Construct graphs from parsed source code"
 homepage = "https://github.com/tree-sitter/tree-sitter-graph/"
 repository = "https://github.com/tree-sitter/tree-sitter-graph/"

src/ast.rs

@@ -9,6 +9,7 @@
 
 use regex::Regex;
 use std::collections::HashMap;
+use std::collections::HashSet;
 use std::fmt;
 use tree_sitter::CaptureQuantifier;
 use tree_sitter::Language;
@@ -24,6 +25,8 @@ pub struct File {
     pub language: Language,
     /// The expected global variables used in this file
     pub globals: Vec<Global>,
+    /// The scoped variables that are inherited by child nodes
+    pub inherited_variables: HashSet<Identifier>,
     /// The combined query of all stanzas in the file
     pub query: Option<Query>,
     /// The list of stanzas in the file
@@ -37,6 +40,7 @@ impl File {
         File {
             language,
             globals: Vec::new(),
+            inherited_variables: HashSet::new(),
             query: None,
             stanzas: Vec::new(),
             shorthands: AttributeShorthands::new(),

src/execution/lazy.rs

@@ -12,6 +12,7 @@ mod values;
 use log::{debug, trace};
 
 use std::collections::HashMap;
+use std::collections::HashSet;
 
 use tree_sitter::QueryCursor;
 use tree_sitter::QueryMatch;
@@ -81,6 +82,7 @@ impl ast::File {
                 &mut lazy_graph,
                 &mut function_parameters,
                 &mut prev_element_debug_info,
+                &self.inherited_variables,
                 &self.shorthands,
                 cancellation_flag,
             )
@@ -92,6 +94,7 @@ impl ast::File {
             functions: config.functions,
             store: &store,
             scoped_store: &scoped_store,
+            inherited_variables: &self.inherited_variables,
             function_parameters: &mut function_parameters,
             prev_element_debug_info: &mut prev_element_debug_info,
             cancellation_flag,
@@ -141,6 +144,7 @@ struct ExecutionContext<'a, 'c, 'g, 'tree> {
     function_parameters: &'a mut Vec<graph::Value>, // re-usable buffer to reduce memory allocations
     prev_element_debug_info: &'a mut HashMap<GraphElementKey, DebugInfo>,
     error_context: StatementContext,
+    inherited_variables: &'a HashSet<Identifier>,
     shorthands: &'a ast::AttributeShorthands,
     cancellation_flag: &'a dyn CancellationFlag,
 }
@@ -152,6 +156,7 @@ pub(self) struct EvaluationContext<'a, 'tree> {
     pub functions: &'a Functions,
     pub store: &'a LazyStore,
     pub scoped_store: &'a LazyScopedVariables,
+    pub inherited_variables: &'a HashSet<Identifier>,
     pub function_parameters: &'a mut Vec<graph::Value>, // re-usable buffer to reduce memory allocations
     pub prev_element_debug_info: &'a mut HashMap<GraphElementKey, DebugInfo>,
     pub cancellation_flag: &'a dyn CancellationFlag,
@@ -177,6 +182,7 @@ impl ast::Stanza {
         lazy_graph: &mut Vec<LazyStatement>,
         function_parameters: &mut Vec<graph::Value>,
         prev_element_debug_info: &mut HashMap<GraphElementKey, DebugInfo>,
+        inherited_variables: &HashSet<Identifier>,
         shorthands: &ast::AttributeShorthands,
         cancellation_flag: &dyn CancellationFlag,
     ) -> Result<(), ExecutionError> {
@@ -203,6 +209,7 @@ impl ast::Stanza {
                 function_parameters,
                 prev_element_debug_info,
                 error_context,
+                inherited_variables,
                 shorthands,
                 cancellation_flag,
             };
@@ -366,6 +373,7 @@ impl ast::Scan {
                 function_parameters: exec.function_parameters,
                 prev_element_debug_info: exec.prev_element_debug_info,
                 error_context: exec.error_context.clone(),
+                inherited_variables: exec.inherited_variables,
                 shorthands: exec.shorthands,
                 cancellation_flag: exec.cancellation_flag,
             };
@@ -431,6 +439,7 @@ impl ast::If {
                     function_parameters: exec.function_parameters,
                     prev_element_debug_info: exec.prev_element_debug_info,
                     error_context: exec.error_context.clone(),
+                    inherited_variables: exec.inherited_variables,
                     shorthands: exec.shorthands,
                     cancellation_flag: exec.cancellation_flag,
                 };
@@ -477,6 +486,7 @@ impl ast::ForIn {
                 function_parameters: exec.function_parameters,
                 prev_element_debug_info: exec.prev_element_debug_info,
                 error_context: exec.error_context.clone(),
+                inherited_variables: exec.inherited_variables,
                 shorthands: exec.shorthands,
                 cancellation_flag: exec.cancellation_flag,
             };
@@ -520,6 +530,7 @@ impl ast::Expression {
             functions: exec.config.functions,
             store: exec.store,
             scoped_store: exec.scoped_store,
+            inherited_variables: exec.inherited_variables,
             function_parameters: exec.function_parameters,
             prev_element_debug_info: exec.prev_element_debug_info,
             cancellation_flag: exec.cancellation_flag,
@@ -569,6 +580,7 @@ impl ast::ListComprehension {
                 function_parameters: exec.function_parameters,
                 prev_element_debug_info: exec.prev_element_debug_info,
                 error_context: exec.error_context.clone(),
+                inherited_variables: exec.inherited_variables,
                 shorthands: exec.shorthands,
                 cancellation_flag: exec.cancellation_flag,
             };
@@ -611,6 +623,7 @@ impl ast::SetComprehension {
                 function_parameters: exec.function_parameters,
                 prev_element_debug_info: exec.prev_element_debug_info,
                 error_context: exec.error_context.clone(),
+                inherited_variables: exec.inherited_variables,
                 shorthands: exec.shorthands,
                 cancellation_flag: exec.cancellation_flag,
             };
@@ -825,6 +838,7 @@ impl ast::AttributeShorthand {
             function_parameters: exec.function_parameters,
             prev_element_debug_info: exec.prev_element_debug_info,
             error_context: exec.error_context.clone(),
+            inherited_variables: exec.inherited_variables,
             shorthands: exec.shorthands,
             cancellation_flag: exec.cancellation_flag,
         };

src/execution/lazy/store.rs

@@ -20,6 +20,7 @@ use crate::execution::error::ExecutionError;
 use crate::execution::error::ResultWithExecutionError;
 use crate::execution::error::StatementContext;
 use crate::graph;
+use crate::graph::SyntaxNodeID;
 use crate::graph::SyntaxNodeRef;
 use crate::Identifier;
 
@@ -151,15 +152,28 @@ impl LazyScopedVariables {
         };
         let values = cell.replace(ScopedValues::Forcing);
         let map = self.force(name, values, exec)?;
-        let result = map
-            .get(&scope)
-            .ok_or(ExecutionError::UndefinedScopedVariable(format!(
-                "{}.{}",
-                scope, name,
-            )))?
-            .clone();
+
+        let mut result = None;
+
+        if let Some(value) = map.get(&scope.index) {
+            result = Some(value.clone());
+        } else if exec.inherited_variables.contains(name) {
+            let mut parent = exec
+                .graph
+                .syntax_nodes
+                .get(&scope.index)
+                .and_then(|n| n.parent());
+            while let Some(scope) = parent {
+                if let Some(value) = map.get(&(scope.id() as u32)) {
+                    result = Some(value.clone());
+                    break;
+                }
+                parent = scope.parent();
+            }
+        }
+
         cell.replace(ScopedValues::Forced(map));
-        Ok(result)
+        result.ok_or_else(|| ExecutionError::UndefinedScopedVariable(format!("{}.{}", scope, name)))
     }
 
     pub(super) fn evaluate_all(&self, exec: &mut EvaluationContext) -> Result<(), ExecutionError> {
@@ -176,7 +190,7 @@ impl LazyScopedVariables {
         name: &Identifier,
         values: ScopedValues,
         exec: &mut EvaluationContext,
-    ) -> Result<HashMap<SyntaxNodeRef, LazyValue>, ExecutionError> {
+    ) -> Result<HashMap<SyntaxNodeID, LazyValue>, ExecutionError> {
         match values {
             ScopedValues::Unforced(pairs) => {
                 let mut map = HashMap::new();
@@ -187,7 +201,7 @@ impl LazyScopedVariables {
                         .with_context(|| format!("Evaluating scope of variable _.{}", name,).into())
                         .with_context(|| debug_info.0.clone().into())?;
                     let prev_debug_info = debug_infos.insert(node, debug_info.clone());
-                    match map.insert(node, value.clone()) {
+                    match map.insert(node.index, value.clone()) {
                         Some(_) => {
                             return Err(ExecutionError::DuplicateVariable(format!(
                                 "{}.{}",
@@ -211,7 +225,7 @@ impl LazyScopedVariables {
 enum ScopedValues {
     Unforced(Vec<(LazyValue, LazyValue, DebugInfo)>),
     Forcing,
-    Forced(HashMap<SyntaxNodeRef, LazyValue>),
+    Forced(HashMap<SyntaxNodeID, LazyValue>),
 }
 
 impl ScopedValues {