From 3297545d4de3e5387d0f42b21b0cfd16b2a66a3e Mon Sep 17 00:00:00 2001
From: Natapat Samutpong <natapat.samutpong@gmail.com>
Date: Sat, 5 Feb 2022 13:53:05 +0700
Subject: [PATCH] feat: `slurp` or file read to string

---
 blspc/src/compiler/compile.rs |  6 +++++-
 blspc/src/vm/vm.rs            | 12 +++++++++++-
 example/quine.blsp            |  3 +++
 3 files changed, 19 insertions(+), 2 deletions(-)
 create mode 100644 example/quine.blsp

diff --git a/blspc/src/compiler/compile.rs b/blspc/src/compiler/compile.rs
index 4eb946e..c4b0cb7 100644
--- a/blspc/src/compiler/compile.rs
+++ b/blspc/src/compiler/compile.rs
@@ -119,7 +119,11 @@ impl Compiler {
                 result.append(&mut self.compile(args[0].clone())?);
                 result.push(Instr::Call { function: "print".to_string() });
             },
-            "read" => { result.push(Instr::Call { function: "read".to_string() }); }
+            "read" => { result.push(Instr::Call { function: "read".to_string() }); },
+            "slurp" => {
+                result.append(&mut self.compile(args[0].clone())?);
+                result.push(Instr::Call { function: "slurp".to_string() });
+            },
 
             "add" | "+" => {
                 let mut lhs = self.compile_atom(&args[0])?;
diff --git a/blspc/src/vm/vm.rs b/blspc/src/vm/vm.rs
index d89f16b..e966539 100644
--- a/blspc/src/vm/vm.rs
+++ b/blspc/src/vm/vm.rs
@@ -1,4 +1,4 @@
-use std::{io, fmt::Display};
+use std::{io::{self, Read}, fmt::Display, fs::File};
 
 use crate::vm::instr::{Instr::{self, *}, Type, Register};
 
@@ -8,6 +8,7 @@ pub enum Error {
     UnknownFunction(String),
     UnknownFunctionCall(String),
     InvalidAriphmeticOperation,
+    FileError(String),
 }
 
 impl Display for Error {
@@ -18,6 +19,7 @@ impl Display for Error {
             Error::UnknownFunction(name) => write!(f, "Unknown function: {}", name),
             Error::UnknownFunctionCall(function) => write!(f, "Unknown function call: {}", function),
             Error::InvalidAriphmeticOperation => write!(f, "Invalid ariphmetic operation"),
+            Error::FileError(msg) => write!(f, "Could not open file: {}", msg),
         }
     }
 }
@@ -217,6 +219,14 @@ impl VM {
                 self.stack.push(input);
                 Ok(())
             },
+            "slurp" => {
+                let file_name = self.stack.pop().unwrap().fmt();
+                let mut result = String::new();
+                match File::open(file_name).and_then(|mut f| f.read_to_string(&mut result)) {
+                    Ok(_) => Ok(self.stack.push(Type::String(result))),
+                    Err(e) => Err(Error::FileError(e.to_string())),
+                }
+            }
             _ => { dbg!(function); Err(Error::UnknownFunctionCall(function.to_string())) },
         }
     }
diff --git a/example/quine.blsp b/example/quine.blsp
new file mode 100644
index 0000000..a0a6fd5
--- /dev/null
+++ b/example/quine.blsp
@@ -0,0 +1,3 @@
+(fun main (do
+    (def file (slurp "quine.blsp"))
+    (print file)))
\ No newline at end of file