Demo visitor with return value

Require rrevenantt/antlr4rust#29

Author: newca12

antlr-calc/src/calc_parser_v3.rs

@@ -0,0 +1,120 @@
+use antlr_rust::tree::{ParseTree, ParseTreeVisitorCompat, Visitable};
+use antlr_rust::InputStream;
+use antlr_rust::{common_token_stream::CommonTokenStream, token_factory::CommonTokenFactory};
+use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
+
+use crate::{AddSubContext, AddSubContextAttrs, MulDivContextAttrs, PrintExprContextAttrs};
+
+use crate::{
+    AssignContext, IdContext, IntContext, LabeledExprLexer, LabeledExprParser,
+    LabeledExprParserContextType, LabeledExprVisitorCompat, MulDivContext,
+};
+
+use crate::PrintExprContext;
+
+use crate::grammar::labeledexprparser::AssignContextAttrs;
+
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub struct Calc3 {
+    pub memory: HashMap<String, i64>,
+    pub res: i64,
+}
+
+impl Default for Calc3 {
+    fn default() -> Self {
+        Calc3 {
+            memory: HashMap::new(),
+            res: 0,
+        }
+    }
+}
+
+pub struct CalcParser {
+    pub(crate) calc: Calc3,
+}
+
+pub fn str_to_calc_v3<'input>(data: &str) -> Calc3 {
+    let tf = CommonTokenFactory::default();
+    let lexer = LabeledExprLexer::new_with_token_factory(InputStream::new(data.into()), &tf);
+    let token_source = CommonTokenStream::new(lexer);
+    let mut parser = LabeledExprParser::new(token_source);
+    let result = parser.prog().expect("parsed unsuccessfully");
+
+    let mut calc_parser = CalcParser {
+        calc: Default::default(),
+    };
+
+    result.accept(&mut calc_parser);
+
+    calc_parser.calc
+}
+
+impl ParseTreeVisitorCompat<'_> for CalcParser {
+    type Node = LabeledExprParserContextType;
+    type Return = i64;
+
+    fn temp_result(&mut self) -> &mut Self::Return {
+        &mut self.calc.res
+    }
+
+    fn aggregate_results(&self, aggregate: Self::Return, next: Self::Return) -> Self::Return {
+        aggregate + &next
+    }
+}
+
+impl LabeledExprVisitorCompat<'_> for CalcParser {
+    fn visit_printExpr(&mut self, ctx: &PrintExprContext) -> Self::Return {
+        let value = ctx.get_text();
+        let res = self.visit(&*ctx.expr().unwrap());
+        println!("{} = {:?}", value, res);
+        self.calc.res
+    }
+
+    fn visit_assign(&mut self, ctx: &AssignContext) -> Self::Return {
+        let id = ctx.ID().unwrap();
+        let value = ctx.expr().unwrap().get_text();
+        println!("{:?} = {}", id, value);
+        self.visit(&*ctx.expr().unwrap());
+        let v = if self.calc.memory.get(&value).is_none() {
+            value.parse().unwrap()
+        } else {
+            *self.calc.memory.get(&value).unwrap()
+        };
+        self.calc.memory.insert(id.get_text(), v);
+        v
+    }
+
+    fn visit_MulDiv(&mut self, ctx: &MulDivContext) -> Self::Return {
+        let left = self.visit(&*ctx.expr(0).unwrap());
+        let right = self.visit(&*ctx.expr(1).unwrap());
+        if ctx.MUL().is_some() {
+            left * right
+        } else {
+            left / right
+        }
+    }
+
+    fn visit_AddSub(&mut self, ctx: &AddSubContext) -> Self::Return {
+        let left = self.visit(&*ctx.expr(0).unwrap());
+        let right = self.visit(&*ctx.expr(1).unwrap());
+        if ctx.ADD().is_some() {
+            left + right
+        } else {
+            left - right
+        }
+    }
+
+    fn visit_id(&mut self, ctx: &IdContext) -> Self::Return {
+        let value = ctx.get_text();
+        if self.calc.memory.get(&value).is_none() {
+            0
+        } else {
+            *self.calc.memory.get(&value).unwrap()
+        }
+    }
+
+    fn visit_int(&mut self, ctx: &IntContext) -> Self::Return {
+        ctx.get_text().parse().unwrap()
+    }
+}

antlr-calc/src/grammar/labeledexprvisitor.rs

@@ -2,7 +2,7 @@
 // Generated from LabeledExpr.g4 by ANTLR 4.8
 use antlr_rust::tree::{ParseTreeVisitor,ParseTreeVisitorCompat};
 use super::labeledexprparser::*;
-use std::mem;
+
 
 /**
  * This interface defines a complete generic visitor for a parse tree produced

antlr-calc/src/lib.rs

@@ -1,13 +1,17 @@
 #![feature(try_blocks)]
 
-pub use calc_parser::*;
+pub use calc_parser::str_to_calc;
+
+pub use calc_parser_v3::str_to_calc_v3;
+use calc_parser_v3::Calc3;
 pub use grammar::*;
 
 pub mod calc_parser;
+pub mod calc_parser_v3;
 pub mod grammar;
 
-pub fn parse(str: &str) -> Calc {
-    str_to_calc(str)
+pub fn parse(str: &str) -> Calc3 {
+    str_to_calc_v3(str)
 }
 
 #[cfg(test)]

antlr-calc/src/main.rs

@@ -1,4 +1,5 @@
 use antlr_calc::str_to_calc;
+use antlr_calc::str_to_calc_v3;
 
 fn main() {
     let data = r#"
@@ -14,4 +15,6 @@ fn main() {
 
     let result = str_to_calc(data);
     println!("{:?}", result);
+    let result = str_to_calc_v3(data);
+    println!("{:?}", result);
 }