From 987df5fb45c32788ee23050d7cf5945ef7cb4250 Mon Sep 17 00:00:00 2001
From: Ross Andrews <ross.andrews@gmail.com>
Date: Sat, 19 Mar 2022 13:07:27 -0500
Subject: [PATCH] Cleaned up .db string handling

---
 vasm/src/ast.rs            |  2 +-
 vasm/src/vasm.pest         |  5 +++--
 vasm/src/vasm_evaluator.rs |  3 ---
 vasm/src/vasm_parser.rs    | 23 ++++++++++++-----------
 4 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/vasm/src/ast.rs b/vasm/src/ast.rs
index cac6b73..3ff4df7 100644
--- a/vasm/src/ast.rs
+++ b/vasm/src/ast.rs
@@ -22,7 +22,6 @@ pub enum Node<'a> {
     RelativeLabel(&'a str),
     AbsoluteOffset(i32),
     RelativeOffset(i32),
-    String(String), // TODO: this shouldn't exist
     Expr(Box<Node<'a>>, Vec<(Operator, Node<'a>)>),
 }
 
@@ -39,6 +38,7 @@ impl<'a> Display for Label<'a> {
 pub enum VASMLine<'a> {
     Instruction(Option<Label<'a>>, Opcode, Option<Node<'a>>),
     Db(Option<Label<'a>>, Node<'a>),
+    StringDb(Option<Label<'a>>, String),
     Org(Option<Label<'a>>, Node<'a>),
     Equ(Label<'a>, Node<'a>),
     LabelDef(Label<'a>),
diff --git a/vasm/src/vasm.pest b/vasm/src/vasm.pest
index 469bd8b..2f208bb 100644
--- a/vasm/src/vasm.pest
+++ b/vasm/src/vasm.pest
@@ -63,9 +63,10 @@ string = ${ "\"" ~ string_inner* ~ "\"" }
 // - .db to embed some data
 // - .equ to define some constants
 instruction = { label_def? ~ opcode ~ expr? }
-db_directive = { label_def? ~ ".db" ~ (expr | string) }
+db_word = { label_def? ~ ".db" ~ expr }
+db_string = { label_def? ~ ".db" ~ string }
 org_directive = { label_def? ~ ".org" ~ expr }
 equ_directive = { label_def ~ ".equ" ~ expr }
 
 // Finally the entire pattern for an assembly line:
-line = { SOI ~ (db_directive | org_directive | equ_directive | instruction | label_def) ~ EOI }
\ No newline at end of file
+line = { SOI ~ (db_word | db_string | org_directive | equ_directive | instruction | label_def) ~ EOI }
\ No newline at end of file
diff --git a/vasm/src/vasm_evaluator.rs b/vasm/src/vasm_evaluator.rs
index d0c5526..2261831 100644
--- a/vasm/src/vasm_evaluator.rs
+++ b/vasm/src/vasm_evaluator.rs
@@ -59,9 +59,6 @@ pub fn eval<'a>(
                 Err(EvalError::UnknownAddress(line_num + offset))
             }
         }
-        Node::String(_) => {
-            unreachable!()
-        }
         Node::Expr(car, cdr) => {
             let car = eval(*car, line_num, line_addresses, scope);
             if let Ok(mut acc) = car {
diff --git a/vasm/src/vasm_parser.rs b/vasm/src/vasm_parser.rs
index f564617..374757d 100644
--- a/vasm/src/vasm_parser.rs
+++ b/vasm/src/vasm_parser.rs
@@ -66,11 +66,11 @@ impl From<Pair<'_>> for Operator {
     }
 }
 
-/// Create a `Node` containing the string represented by a given pair. Since the pair will
+/// Create a String containing the string represented by a given pair. Since the pair will
 /// reference bytes containing escape sequences, this isn't the same as an &str to the
 /// original code; this is a new string translating those escape sequences to their actual
 /// bytes.
-fn create_string_node(pair: Pair) -> Node {
+fn create_string(pair: Pair) -> String {
     let mut string = String::with_capacity(pair.as_str().len());
     for inner in pair.into_inner() {
         let string_inner = inner.as_str();
@@ -84,7 +84,7 @@ fn create_string_node(pair: Pair) -> Node {
             _ => string.push_str(string_inner),
         }
     }
-    Node::String(string)
+    string
 }
 
 /// Create a `Node` containing the line offset represented by a pair.
@@ -134,7 +134,6 @@ fn parse(pair: Pair) -> Node {
         Rule::oct_number => {
             Node::Number(i32::from_str_radix(pair.as_str().get(2..).unwrap(), 8).unwrap())
         }
-        Rule::string => create_string_node(pair),
         Rule::label => Node::Label(pair.as_str()),
         Rule::relative_label => Node::RelativeLabel(pair.as_str().get(1..).unwrap()),
         Rule::absolute_line_offset | Rule::relative_line_offset => create_line_offset_node(pair),
@@ -167,12 +166,18 @@ pub fn parse_vasm_line(line: &str) -> Result<VASMLine, ParseError<'_>> {
                 .map(|expr| shake(parse(expr)));
             return Ok(VASMLine::Instruction(label, opcode, argument));
         }
-        Rule::db_directive => {
+        Rule::db_word => {
             let mut iter = line.into_inner().peekable();
             let label = optional_label(iter.next_if(|pair| pair.as_rule() == Rule::label_def));
             let argument = shake(parse(iter.next().unwrap()));
             return Ok(VASMLine::Db(label, argument));
         }
+        Rule::db_string => {
+            let mut iter = line.into_inner().peekable();
+            let label = optional_label(iter.next_if(|pair| pair.as_rule() == Rule::label_def));
+            let argument = create_string(iter.next().unwrap());
+            return Ok(VASMLine::StringDb(label, argument));
+        }
         Rule::org_directive => {
             let mut iter = line.into_inner().peekable();
             let label = optional_label(iter.next_if(|pair| pair.as_rule() == Rule::label_def));
@@ -203,10 +208,6 @@ mod test {
         Node::Number(number)
     }
 
-    fn string(s: &str) -> Node<'static> {
-        Node::String(s.to_string())
-    }
-
     #[test]
     fn test_parse() {
         assert_eq!(
@@ -264,11 +265,11 @@ mod test {
     fn test_dbs() {
         assert_eq!(
             parse_vasm_line(".db \"blah\""),
-            Ok(VASMLine::Db(None, string("blah")))
+            Ok(VASMLine::StringDb(None, "blah".into()))
         );
         assert_eq!(
             parse_vasm_line(".db \"blah\\twith escapes\\0\""),
-            Ok(VASMLine::Db(None, string("blah\twith escapes\0")))
+            Ok(VASMLine::StringDb(None, "blah\twith escapes\0".into()))
         );
         assert_eq!(
             parse_vasm_line("foo: .db 47"),