refactor: Implement visitor pattern for constant_map

Author: ngeor

rusty_linter/src/pre_linter/const_rules.rs

@@ -1,13 +1,36 @@
-use crate::core::ConstLookup;
-use rusty_common::CaseInsensitiveString;
-use rusty_parser::BareName;
-use rusty_variant::Variant;
 use std::collections::HashMap;
 
+use rusty_common::{AtPos, CaseInsensitiveString, Positioned};
+use rusty_parser::{BareName, Constant, Name};
+use rusty_variant::Variant;
+
+use crate::core::*;
+
 pub type ConstantMap = HashMap<BareName, Variant>;
 
 impl ConstLookup for ConstantMap {
     fn get_resolved_constant(&self, name: &CaseInsensitiveString) -> Option<&Variant> {
         self.get(name)
     }
 }
+
+impl Visitor<Constant> for ConstantMap {
+    // calculate global constant values
+    fn visit(&mut self, element: &Constant) -> VisitResult {
+        let (name_pos, expression_pos) = element.into();
+        let Positioned { element: name, pos } = name_pos;
+        let bare_name: &BareName = name.bare_name();
+        (match self.get(bare_name) {
+            Some(_) => Err(LintError::DuplicateDefinition.at(pos)),
+            _ => Ok(()),
+        })
+        .and_then(|_| self.resolve_const(expression_pos))
+        .and_then(|v| match name {
+            Name::Bare(_) => Ok(v),
+            Name::Qualified(_, qualifier) => v.cast(*qualifier).map_err(|e| e.at(expression_pos)),
+        })
+        .map(|casted| {
+            self.insert(bare_name.clone(), casted);
+        })
+    }
+}

rusty_linter/src/pre_linter/constant_map.rs

@@ -1,5 +1,4 @@
 use crate::core::*;
-use crate::pre_linter::const_rules::global_const;
 use crate::pre_linter::sub_program_context::SubprogramContext;
 use crate::pre_linter::{ConstantMap, PreLinterResult};
 use rusty_common::*;
@@ -116,7 +115,7 @@ impl Visitor<SubImplementation> for MainContext {
 impl Visitor<Statement> for MainContext {
     fn visit(&mut self, s: &Statement) -> VisitResult {
         match s {
-            Statement::Const(c) => global_const(&mut self.global_constants, c),
+            Statement::Const(c) => self.global_constants.visit(c),
             _ => Ok(()),
         }
     }

rusty_linter/src/pre_linter/main.rs

@@ -1,4 +1,3 @@
-mod const_rules;
 mod constant_map;
 mod main;
 mod pre_linter_result;