enable an option to disable readline

Cargo.toml

@@ -1,17 +1,21 @@
 [package]
 name = "scryer-prolog"
-version = "0.8.11"
+version = "0.8.12"
 authors = ["Mark Thom <markjordanthom@gmail.com>"]
 repository = "https://github.com/mthom/scryer-prolog"
 description = "A modern Prolog implementation written mostly in Rust."
 license = "BSD-3-Clause"
 
+[features]
+default = ["readline_rs_compat"]
+
 [dependencies]
+cfg-if = "0.1.7"
 downcast = "0.9.1"
 num = "0.2"
 ordered-float = "0.5.0"
 prolog_parser = "0.8.1"
-readline_rs_compat = "0.1.5"
+readline_rs_compat = { version = "0.1.5", optional = true }
 
 [dependencies.termion]
 version = "1.4.0"

README.md

@@ -114,6 +114,13 @@ readline:
 /opt/local/lib
 ```
 
+If you'd like to disable readline (and the need for linking to it),
+install with the line
+
+```
+cargo install scryer-prolog --no-default-features
+```
+
 You can find the `scryer-prolog` executable in `~/.cargo/bin`.
 
 Note on compatibility: Scryer Prolog should work on Linux, Mac OS X,

src/main.rs

@@ -1,7 +1,13 @@
+#[macro_use] extern crate cfg_if;
 #[macro_use] extern crate downcast;
 #[macro_use] extern crate prolog_parser;
 
+cfg_if! {
+    if #[cfg(feature = "readline_rs_compat")] {
         extern crate readline_rs_compat;
+    }
+}
+
 extern crate termion;
 
 mod prolog;
@@ -20,7 +26,8 @@ fn prolog_repl() {
     let mut wam = Machine::new();
 
     loop {
-        set_line_mode(LineMode::Single);
+        #[cfg(feature = "readline_rs_compat")]
+        readline::set_line_mode(readline::LineMode::Single);
 
         match toplevel_read_line() {
             Ok(Input::TermString(buffer)) => {
@@ -32,9 +39,10 @@ fn prolog_repl() {
                 print(&mut wam, result)
             },
             Ok(Input::Batch) => {
-                set_line_mode(LineMode::Multi);
+                #[cfg(feature = "readline_rs_compat")]
+                readline::set_line_mode(readline::LineMode::Multi);
 
-                let src = match read_batch("") {
+                let src = match readline::read_batch("") {
                     Ok(src) => src,
                     Err(e) => {
                         println!("{}", e);
@@ -42,7 +50,7 @@ fn prolog_repl() {
                     }
                 };
 
-                let result = compile_user_module(&mut wam, src.as_bytes());
+                let result = compile_user_module(&mut wam, &src[0 ..]);
                 print(&mut wam, result);
             },
             Ok(Input::Clear) => {
@@ -57,6 +65,7 @@ fn prolog_repl() {
 }
 
 fn main() {
-    readline_initialize();
+    #[cfg(feature = "readline_rs_compat")]
+    readline::readline_initialize();
     prolog_repl();
 }

src/prolog/read.rs

@@ -11,8 +11,6 @@ use prolog::machine::machine_state::MachineState;
 use std::collections::VecDeque;
 use std::io::Read;
 
-use readline_rs_compat::readline::*;
-
 type SubtermDeque = VecDeque<(usize, usize)>;
 
 impl<'a> TermRef<'a> {
@@ -29,9 +27,14 @@ impl<'a> TermRef<'a> {
 pub enum Input {
     Clear,
     Batch,
-    TermString(&'static str)
+    TermString(String)
 }
 
+#[cfg(feature = "readline_rs_compat")]
+pub mod readline
+{
+    use readline_rs_compat::readline::*;
+
     #[derive(Clone, Copy)]
     pub enum LineMode {
         Single,
@@ -100,26 +103,16 @@ pub fn readline_initialize() {
             panic!("initialize_rl() failed with return code {}", rc);
         }
 
+        unsafe {
+            rl_startup_hook = insert_query_prompt;
+        }
+
         bind_key_rl('.' as i32, bind_end_key);
         bind_key_rl('\n' as i32, bind_cr);
         bind_key_rl('\r' as i32, bind_cr);
         bind_keyseq_rl("\\C-d", bind_end_chord);
     }
 
-pub fn read_batch(prompt: &str) -> Result<&'static str, SessionError> {
-    match readline_rl(prompt) {
-        Some(input) => Ok(input),
-        None => Err(SessionError::UserPrompt)
-    }
-}
-
-fn read_line(prompt: &str) -> Result<&'static str, SessionError> {
-    match readline_rl(prompt) {
-        Some(input) => Ok(input),
-        None => Err(SessionError::UserPrompt)
-    }
-}
-
     unsafe extern "C" fn insert_query_prompt() -> i32 {
         if let LineMode::Single = LINE_MODE {
             insert_text_rl("?- ");
@@ -128,13 +121,67 @@ unsafe extern "C" fn insert_query_prompt() -> i32 {
         0
     }
 
-pub fn toplevel_read_line() -> Result<Input, SessionError>
-{
-    unsafe {
-        rl_startup_hook = insert_query_prompt;
+    pub fn read_batch(prompt: &str) -> Result<Vec<u8>, ::SessionError> {
+        match readline_rl(prompt) {
+            Some(input) => Ok(Vec::from(input.as_bytes())),
+            None => Err(::SessionError::UserPrompt)
+        }
     }
 
-    let buffer = read_line("")?;
+    pub fn read_line(prompt: &str) -> Result<String, ::SessionError> {
+        match readline_rl(prompt) {
+            Some(input) => Ok(String::from(input)),
+            None => Err(::SessionError::UserPrompt)
+        }
+    }
+}
+
+#[cfg(not(feature = "readline_rs_compat"))]
+pub mod readline
+{
+    use std::io::{BufRead, Read, stdin, stdout, Write};
+    
+    pub fn read_batch(_: &str) -> Result<Vec<u8>, ::SessionError> {
+        let mut buf = vec![];
+
+        let stdin = stdin();
+        let mut stdin = stdin.lock();
+
+        match stdin.read_to_end(&mut buf) {
+            Ok(_) => Ok(buf),
+            _ => Err(::SessionError::UserPrompt)
+        }
+    }
+
+    pub fn read_line(_: &str) -> Result<String, ::SessionError> {
+        print!("?- ");
+        stdout().flush().unwrap();
+
+        let stdin = stdin();
+        let stdin = stdin.lock();
+        
+        let mut buf = "?- ".to_string();
+        
+        for line in stdin.lines() {
+            match line {
+                Ok(line) => {
+                    buf += &line;
+                    
+                    if line.trim().ends_with(".") {
+                        break;
+                    }
+                },
+                _ => return Err(::SessionError::UserPrompt)
+            }
+        }
+
+        Ok(buf)
+    }
+}
+
+pub fn toplevel_read_line() -> Result<Input, SessionError>
+{
+    let buffer = readline::read_line("")?;
 
     Ok(match &*buffer.trim() {
         "?- [clear]." => Input::Clear,