Initial commit.

src/main.rs

@@ -0,0 +1,76 @@
+mod l0;
+
+use l0::ast::{Atom, Program, Term, TopLevel, Var};
+use l0::codegen::{compile_fact, compile_query};
+use l0::machine::{MachineState};
+
+use std::io::{self, Write};
+
+fn print_instructions(program : Program) {
+    for instruction in program {
+        println!("{:}", instruction);        
+    }
+}
+
+fn l0_repl<'a>() {
+    let mut ms = MachineState::new();
+    
+    loop {
+        print!("l0> ");
+        io::stdout().flush();
+
+        let mut buffer = String::new();
+        io::stdin().read_line(&mut buffer).unwrap();
+        
+        let result = l0::l0_parser::parse_TopLevel(&*buffer);
+
+        if &*buffer == "quit\n" {
+            break;
+        } else if &*buffer == "clear\n" {
+            ms = MachineState::new();
+        }        
+        
+        match result {            
+            Ok(TopLevel::Fact(fact)) => {                
+                let program = compile_fact(&fact);
+                
+                ms = MachineState::new();                
+                ms.program = Some(program);
+
+                println!("Program stored.");
+            },
+            Ok(TopLevel::Query(query)) => {
+                if let Some(program) = ms.program.clone().take() {                
+                    let query = compile_query(&query);
+                
+                    for instruction in query {
+                        ms.execute(instruction);
+                    }
+
+                    for instruction in program {                    
+                        ms.execute(instruction);
+
+                        if ms.fail {                            
+                            break;
+                        }
+                    }                    
+                
+                    if ms.fail {
+                        println!("no");
+                    } else {
+                        println!("yes");
+                    }
+
+                    ms.reset_heap();
+                } else {
+                    println!("No program to speak of.");
+                }
+            },                                        
+            Err(_) => println!("Grammatical error of some kind!"),
+        };        
+    }
+}
+
+fn main() {
+    l0_repl();
+}