Add string reference word

henceforth/examples/test.fth

@@ -1,2 +1,3 @@
-depth dup dup dup dup dup debug
+." test-string" cr
+r" bliblablub" debug
 

henceforth/src/lib/compiler.rs

@@ -55,7 +55,11 @@ impl Data {
                     instructions.push(match mode.as_str() {
                         "." => {
                             let id = self.strings.insert_full(string).0;
-                            Instruction::DotQuote(id)
+                            Instruction::StringPrint(id)
+                        }
+                        "r" => {
+                            let id = self.strings.insert_full(string).0;
+                            Instruction::StringReference(id)
                         }
                         "asm" => Instruction::AsmQuote(string),
                         _ => bail!("Unknown string mode: {}", mode),

henceforth/src/lib/compiler/instruction.rs

@@ -31,7 +31,8 @@ pub enum Instruction {
     Space,
     Spaces,
     Cr,
-    DotQuote(usize),
+    StringPrint(usize),
+    StringReference(usize),
     Count,
     Not,
     And,
@@ -653,7 +654,7 @@ impl compiler::Compilable<compiler::Data, hence::parser::ast::Body> for Instruct
                     args: vec![hence::arg::Arg::Variable("CORE_MEM_CHR".to_string())],
                 },
             ]),
-            Instruction::DotQuote(x) => {
+            Instruction::StringPrint(x) => {
                 let loop_label = format!("loop_strings_{}", x);
                 let data_label = format!("data_strings_{}", x);
                 let data_end_label = format!("data_strings_end_{}", x);
@@ -719,6 +720,16 @@ impl compiler::Compilable<compiler::Data, hence::parser::ast::Body> for Instruct
                     },
                 ])
             }
+            Instruction::StringReference(x) => Ok(vec![
+                hence::parser::ast::Node::Call {
+                    name: "push".to_string(),
+                    arg: Some(hence::arg::Arg::Variable(format!("data_strings_end_{}", x))),
+                },
+                hence::parser::ast::Node::Call {
+                    name: "push".to_string(),
+                    arg: Some(hence::arg::Arg::Variable(format!("data_strings_{}", x))),
+                },
+            ]),
             Instruction::Count => Ok(vec![]),
             Instruction::Not => Ok(vec![
                 hence::parser::ast::Node::MacroCall {