fix hlorenzi#112: add #once directive

src/asm/parser/file.rs

@@ -7,10 +7,17 @@ pub fn parse_file<TFilename: Into<String>>(
     fileserver: &dyn util::FileServer,
     filename: TFilename,
     span: Option<&diagn::Span>,
-    parsed_filenames: &mut std::collections::HashSet<String>)
+    parsed_filenames: &mut std::collections::HashSet<String>,
+    once_filenames: &mut std::collections::HashSet<String>)
     -> Result<(), ()>
 {
     let filename = filename.into();
+
+    if once_filenames.contains(&filename)
+    {
+        return Ok(());
+    }
+
     let chars = fileserver.get_chars(report.clone(), &filename, span)?;
     let tokens = syntax::tokenize(report.clone(), &filename, &chars)?;
     let parser = syntax::Parser::new(Some(report.clone()), &tokens);
@@ -25,6 +32,7 @@ pub fn parse_file<TFilename: Into<String>>(
         filename: std::rc::Rc::new(filename.clone()),
         parser,
         parsed_filenames,
+        once_filenames,
     };
 
     //println!("{:#?}", state.parser.tokens.iter().map(|t| t.kind).collect::<Vec<_>>());
@@ -33,7 +41,7 @@ pub fn parse_file<TFilename: Into<String>>(
     {
         parse_line(&mut state)?;
     }
-	
+    
     parsed_filenames.remove(&filename);
 	Ok(())
 }
@@ -109,6 +117,7 @@ pub fn parse_directive(state: &mut asm::parser::State)
             "ruledef" | "cpudef" => asm::parser::parse_directive_ruledef(state, &tk_directive, true)?,
             "subruledef" | "tokendef" => asm::parser::parse_directive_ruledef(state, &tk_directive, false)?,
             "include" => asm::parser::parse_directive_include(state)?,
+            "once" => asm::parser::parse_directive_once(state)?,
             "res" => asm::parser::parse_directive_res(state)?,
             "align" => asm::parser::parse_directive_align(state)?,
             "labelalign" => asm::parser::parse_directive_labelalign(state)?,

src/asm/parser/include.rs

@@ -29,5 +29,16 @@ pub fn parse_directive_include(
         state.fileserver,
         new_filename,
         Some(&tk_filename.span),
-        state.parsed_filenames)
+        state.parsed_filenames,
+        state.once_filenames)
+}
+
+
+pub fn parse_directive_once(
+    state: &mut asm::parser::State)
+    -> Result<(), ()>
+{
+    state.once_filenames.insert(state.filename.as_ref().clone()); 
+
+    Ok(())
 }

src/asm/parser/state.rs

@@ -9,4 +9,5 @@ pub struct State<'a>
     pub filename: std::rc::Rc<String>,
     pub parser: syntax::Parser<'a>,
     pub parsed_filenames: &'a mut std::collections::HashSet<String>,
+    pub once_filenames: &'a mut std::collections::HashSet<String>,
 }

src/asm/state.rs

@@ -124,6 +124,7 @@ impl Assembler
 					fileserver,
 					filename,
 					None,
+					&mut std::collections::HashSet::new(),
 					&mut std::collections::HashSet::new());
 
 				if pass_report.has_errors() || result.is_err()

tests/once/1.asm

@@ -0,0 +1,9 @@
+#ruledef
+{
+    emit {x: u8} => x
+}
+
+#include "once.asm"
+#include "once.asm"
+#include "once.asm"
+emit $ ; = 0xcd01

tests/once/once.asm

@@ -0,0 +1,2 @@
+#once
+#d8 0xCD