From f355183b8d44d34f88996f3c3ab17e4501f00d65 Mon Sep 17 00:00:00 2001
From: Natapat Samutpong <natapat.samutpong@gmail.com>
Date: Sat, 5 Feb 2022 09:48:52 +0700
Subject: [PATCH] feat: `read`

---
 README.md                     |  1 +
 blspc/src/compiler/compile.rs |  5 ++++
 blspc/src/vm/instr.rs         | 14 ++++--------
 blspc/src/vm/parser.rs        |  2 +-
 blspc/src/vm/vm.rs            | 43 ++++++++++++++++++++---------------
 example/input.blsp            |  4 ++++
 6 files changed, 40 insertions(+), 29 deletions(-)
 create mode 100644 example/input.blsp

diff --git a/README.md b/README.md
index 711a395..e3b7c0a 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,7 @@ DONE:
   - Function definition: `fun`
   - Variable definition: `let`
   - Do blocks: `do`
+  - User input: `read`
   - Printing: `print`
   - Condition: `if`
   - Math: 
diff --git a/blspc/src/compiler/compile.rs b/blspc/src/compiler/compile.rs
index 82031cb..418c25e 100644
--- a/blspc/src/compiler/compile.rs
+++ b/blspc/src/compiler/compile.rs
@@ -106,6 +106,11 @@ impl Compiler {
                 result.push(Instr::Push { value: Type::Int(1) });
                 result.push(Instr::Call);
             },
+            "read" => {
+                result.push(Instr::Push { value: Type::Int(0) }); // read doesn't need an argument
+                result.push(Instr::Push { value: Type::Int(2) });
+                result.push(Instr::Call);
+            }
             "add" | "+" => {
                 let mut lhs = self.compile_atom(&args[0])?;
                 result.append(&mut lhs);
diff --git a/blspc/src/vm/instr.rs b/blspc/src/vm/instr.rs
index 0c6b93e..eed6af8 100644
--- a/blspc/src/vm/instr.rs
+++ b/blspc/src/vm/instr.rs
@@ -13,7 +13,6 @@ pub enum Type {
 }
 
 impl Type {
-
     pub fn is_null(&self) -> bool {
         match self {
             Type::Null => true,
@@ -102,10 +101,10 @@ impl Div for Type {
 impl Display for Type {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match self {
-            Type::Int(i)     => write!(f, ":{}", i),
-            Type::Float(fl)  => write!(f, ":{}", fl),
-            Type::Boolean(b) => write!(f, ":{}", b),
-            Type::String(s)  => write!(f, "$\"{}\"", s),
+            Type::Int(i)     => write!(f, "{}", i),
+            Type::Float(fl)  => write!(f, "{}", fl),
+            Type::Boolean(b) => write!(f, "{}", b),
+            Type::String(s)  => write!(f, "\"{}\"", s),
             _ => unreachable!(),
         }
     }
@@ -115,11 +114,6 @@ impl FromStr for Type {
     type Err = String;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        if !s.starts_with("$") && !s.starts_with(":") {
-            return Err(format!("Invalid literal: {}", s));
-        }
-
-        let s = &s[1..];
         match s {
             "true"  => Ok(Type::Boolean(true)),
             "false" => Ok(Type::Boolean(false)),
diff --git a/blspc/src/vm/parser.rs b/blspc/src/vm/parser.rs
index 90c4647..e0c2506 100644
--- a/blspc/src/vm/parser.rs
+++ b/blspc/src/vm/parser.rs
@@ -2,7 +2,7 @@ use regex::Regex;
 
 use crate::vm::instr::*;
 
-const REGEX: &str = r###"[^\s\$";]+|\$"[^"]*"|;.*"###;
+const REGEX: &str = r###"[^\s\$";]+|"[^"]*"|;.*"###;
 
 macro_rules! value    { ($s:expr) => { $s.parse::<Type>().unwrap() }; }
 macro_rules! register { ($s:expr) => { $s.parse::<Register>().unwrap() }; }
diff --git a/blspc/src/vm/vm.rs b/blspc/src/vm/vm.rs
index d5da987..58027a6 100644
--- a/blspc/src/vm/vm.rs
+++ b/blspc/src/vm/vm.rs
@@ -1,4 +1,4 @@
-use std::fmt::Display;
+use std::{io, fmt::Display};
 
 use crate::vm::instr::{Instr::{self, *}, Type, Register};
 
@@ -81,7 +81,7 @@ impl VM {
                 Call => {
                     let index = &self.stack.pop().unwrap();
                     let args = &self.stack.pop().unwrap();
-                    call(index, args, self.instr_pointer)?;
+                    self.call(index, args, self.instr_pointer)?;
                     continue 'tco;
                 },
                 Push { value } => {
@@ -176,6 +176,29 @@ impl VM {
         }
         Err(Error::UnknownFunction(name))
     }
+
+    fn call(&mut self, index: &Type, args: &Type, line: isize) -> Result<(), Error> {
+        match index {
+            Type::Int(i) => {
+                match i {
+                    0 => Err(Error::UnknownFunctionCall(line, 0)),
+                    1 => {
+                        print!("{}", args.fmt());
+                        Ok(())
+                    },
+                    2 => {
+                        let mut input = String::new();
+                        io::stdin().read_line(&mut input).unwrap();
+                        let input = input.trim().parse::<Type>().unwrap();
+                        self.stack.push(input);
+                        Ok(())
+                    }
+                    _ => Err(Error::UnknownFunctionCall(line, *i as isize)),
+                }
+            }
+            _ => {dbg!(index); Err(Error::UnknownFunctionCall(line, -1))},
+        }
+    }
 }
 
 fn print_debug(vm: &VM, curr_instr: &Instr) {
@@ -184,20 +207,4 @@ fn print_debug(vm: &VM, curr_instr: &Instr) {
     println!("regis: {:?}", regs);
     println!("stack: {:?}", vm.stack);
     println!("currn: {} {}", vm.instr_pointer, curr_instr);
-}
-
-fn call(index: &Type, args: &Type, line: isize) -> Result<(), Error> {
-    match index {
-        Type::Int(i) => {
-            match i {
-                0 => Err(Error::UnknownFunctionCall(line, 0)),
-                1 => {
-                    println!("{}", args.fmt());
-                    Ok(())
-                },
-                _ => Err(Error::UnknownFunctionCall(line, *i as isize)),
-            }
-        }
-        _ => {dbg!(index); Err(Error::UnknownFunctionCall(line, -1))},
-    }
 }
\ No newline at end of file
diff --git a/example/input.blsp b/example/input.blsp
new file mode 100644
index 0000000..22b8001
--- /dev/null
+++ b/example/input.blsp
@@ -0,0 +1,4 @@
+(fun main (do
+    (let in (read))
+    (print "Your input was: ")
+    (print in)))