make toplevel more consistent with answers, depend on readline package without renaming.

Cargo.lock

@@ -1,170 +0,0 @@
-[[package]]
-name = "downcast"
-version = "0.9.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "libc"
-version = "0.2.50"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "num"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-bigint 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-complex 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-iter 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-rational 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "num-bigint"
-version = "0.2.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "num-complex"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "num-integer"
-version = "0.1.39"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "num-iter"
-version = "0.1.37"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "num-rational"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-bigint 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "num-traits"
-version = "0.1.43"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "num-traits"
-version = "0.2.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "ordered-float"
-version = "0.5.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num-traits 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
- "unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "prolog_parser"
-version = "0.8.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "num 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "ordered-float 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "readline-rs"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "redox_syscall"
-version = "0.1.51"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "redox_termios"
-version = "0.1.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "redox_syscall 0.1.51 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "scryer-prolog"
-version = "0.8.6"
-dependencies = [
- "downcast 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "num 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "ordered-float 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "prolog_parser 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "readline-rs 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "termion"
-version = "1.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "libc 0.2.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_syscall 0.1.51 (registry+https://github.com/rust-lang/crates.io-index)",
- "redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "unreachable"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "void"
-version = "1.0.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[metadata]
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-"checksum libc 0.2.50 (registry+https://github.com/rust-lang/crates.io-index)" = "aab692d7759f5cd8c859e169db98ae5b52c924add2af5fbbca11d12fefb567c1"
-"checksum num 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "cf4825417e1e1406b3782a8ce92f4d53f26ec055e3622e1881ca8e9f5f9e08db"
-"checksum num-bigint 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "57450397855d951f1a41305e54851b1a7b8f5d2e349543a02a2effe25459f718"
-"checksum num-complex 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "107b9be86cd2481930688277b675b0114578227f034674726605b8a482d8baf8"
-"checksum num-integer 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)" = "e83d528d2677f0518c570baf2b7abdcf0cd2d248860b68507bdcb3e91d4c0cea"
-"checksum num-iter 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "af3fdbbc3291a5464dc57b03860ec37ca6bf915ed6ee385e7c6c052c422b2124"
-"checksum num-rational 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4e96f040177bb3da242b5b1ecf3f54b5d5af3efbbfb18608977a5d2767b22f10"
-"checksum num-traits 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)" = "92e5113e9fd4cc14ded8e499429f396a20f98c772a47cc8622a736e1ec843c31"
-"checksum num-traits 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0b3a5d7cc97d6d30d8b9bc8fa19bf45349ffe46241e8816f50f62f6d6aaabee1"
-"checksum ordered-float 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7eb5259643245d3f292c7a146b2df53bba24d7eab159410e648eb73dc164669d"
-"checksum prolog_parser 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "6da85e0cfa5a604edf65f753e629db37bfd04af93a09a1df5576d2197a2f7af3"
-"checksum readline-rs 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f35410ab92501753b66a269387df7a8162daeaf816f6528ba8b07b34f0d80c99"
-"checksum redox_syscall 0.1.51 (registry+https://github.com/rust-lang/crates.io-index)" = "423e376fffca3dfa06c9e9790a9ccd282fafb3cc6e6397d01dbf64f9bacc6b85"
-"checksum redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7e891cfe48e9100a70a3b6eb652fef28920c117d366339687bd5576160db0f76"
-"checksum termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "689a3bdfaab439fd92bc87df5c4c78417d3cbe537487274e9b0b2dce76e92096"
-"checksum unreachable 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "382810877fe448991dfc7f0dd6e3ae5d58088fd0ea5e35189655f84e6814fa56"
-"checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"

Cargo.toml

@@ -1,8 +1,6 @@
-cargo-features = ["rename-dependency"]
-
 [package]
 name = "scryer-prolog"
-version = "0.8.7"
+version = "0.8.8"
 authors = ["Mark Thom <markjordanthom@gmail.com>"]
 repository = "https://github.com/mthom/scryer-prolog"
 description = "A modern Prolog implementation written mostly in Rust."
@@ -13,7 +11,7 @@ downcast = "0.9.1"
 num = "0.2"
 ordered-float = "0.5.0"
 prolog_parser = "0.8.1"
-readline_rs = { package = "readline-rs", version = "0.1.2" }
+readline_rs_compat = { version = "0.1.3" }
 
 [dependencies.termion]
 version = "1.4.0"

README.md

@@ -218,11 +218,11 @@ To enter a multi-clause predicate, the directive "[user]" is used.
 
 For example,
 ```
-prolog> [user]
+?- [user].
 (type Enter + Ctrl-D to terminate the stream when finished)
 p(f(f(X)), h(W), Y) :- g(W), h(W), f(X).
 p(X, Y, Z) :- h(Y), z(Z).
-prolog> [user]
+?- [user].
 (type Enter + Ctrl-D to terminate the stream when finished)
 h(x). h(y).
 h(z).
@@ -232,7 +232,7 @@ input stream. The instructive message is always printed.
 
 Queries are issued as
 ```
-prolog> ?- p(X, Y, Z).
+?- p(X, Y, Z).
 ```
 
 Pressing `SPACE` will backtrack through other possible answers, if any exist.
@@ -241,10 +241,11 @@ Pressing `.` will abort the search and return to the prompt.
 Wildcards work as well:
 
 ```
-prolog> [user]
+?- [user].
+(type Enter + Ctrl-D to terminate the stream when finished)
 member(X, [X|_]).
 member(X, [_|Xs]) :- member(X, Xs).
-prolog> ?- member(X, [a, b, c]).
+?- member(X, [a, b, c]).
 true .
 X = a ;
 X = b ;
@@ -253,13 +254,12 @@ false.
 ```
 and so do conjunctive queries:
 ```
-prolog> [user]
+?- [user].
+(type Enter + Ctrl-D to terminate the stream when finished)
 f(X) :- g(X).
-prolog> [user]
 g(x). g(y). g(z).
-prolog> [user]
 h(call(f, X)).
-prolog> ?- h(X), X.
+?- h(X), X.
 true .
 X = call(f, x) ;
 X = call(f, y) ;
@@ -270,13 +270,18 @@ Note that the values of variables belonging to successful queries are
 printed out, on one line each. Uninstantiated variables are denoted by
 a number preceded by an underscore (`X = _0` in an example above).
 
+To quit scryer-prolog, type
+```
+?- halt.
+```
+
 ### Dynamic operators
 
 Scryper supports dynamic operators. Using the built-in
 arithmetic operators with the usual precedences,
 
 ```
-prolog> ?- write_canonical(-5 + 3 - (2 * 4) // 8).
+?- write_canonical(-5 + 3 - (2 * 4) // 8).
 -(+(-(5), 3), //(*(2, 4), 8))
 true.
 ```
@@ -314,15 +319,16 @@ operators and predicates are hidden in their own modules that have not
 been exported to the toplevel. To export them, write
 
 ```
-prolog> :- use_module(library(lists)).
+?- use_module(library(lists)).
-prolog> :- use_module(library(control)).
+?- use_module(library(control)).
 ```
 
 The [user] prompt can also be used to define modules inline at the
 REPL:
 
 ```
-prolog> [user]
+?- [user].
+(type Enter + Ctrl-D to terminate the stream when finished)
 :- module(test, [local_member/2]).
 :- use_module(library(lists)).
 
@@ -332,7 +338,7 @@ local_member(X, Xs) :- member(X, Xs).
 `use_module` directives can be qualified by adding a list of imports:
 
 ```
-prolog> :- use_module(library(lists), [member/2]).
+?- use_module(library(lists), [member/2]).
 ```
 
 A qualified `use_module` can be used to remove imports from the
@@ -342,5 +348,5 @@ The `(:)/2` operator resolves calls to predicates that might not be
 imported to the current working namespace:
 
 ```
-prolog> ?- lists:member(X, Xs).
+?- lists:member(X, Xs).
 ```

src/main.rs

@@ -1,7 +1,7 @@
 #[macro_use] extern crate downcast;
 #[macro_use] extern crate prolog_parser;
 
-extern crate readline_rs;
+extern crate readline_rs_compat;
 extern crate termion;
 
 mod prolog;
@@ -34,7 +34,7 @@ fn prolog_repl() {
             Ok(Input::Batch) => {
                 set_line_mode(LineMode::Multi);
 
-                let src = match read_line("") {
+                let src = match read_batch("") {
                     Ok(src) => src,
                     Err(e) => {
                         println!("{}", e);
@@ -45,7 +45,6 @@ fn prolog_repl() {
                 let result = compile_user_module(&mut wam, src.as_bytes());
                 print(&mut wam, result);
             },
-            Ok(Input::Quit) => break,
             Ok(Input::Clear) => {
                 wam.clear();
                 continue;

src/prolog/machine/toplevel.rs

@@ -231,8 +231,10 @@ fn setup_qualified_import(mut terms: Vec<Box<Term>>) -> Result<UseModuleExport,
     }
 }
 
-fn setup_declaration(term: Term) -> Result<Declaration, ParserError>
+fn setup_declaration(mut terms: Vec<Box<Term>>) -> Result<Declaration, ParserError>
 {
+    let term = *terms.pop().unwrap();
+    
     match term {
         Term::Clause(_, name, mut terms, _) =>
             if name.as_str() == "op" && terms.len() == 3 {
@@ -592,7 +594,8 @@ impl RelationWorker {
         }
     }
 
-    fn setup_query(&mut self, indices: &mut CompositeIndices, terms: Vec<Box<Term>>, blocks_cuts: bool)
+    fn setup_query(&mut self, indices: &mut CompositeIndices, terms: Vec<Box<Term>>,
+                   blocks_cuts: bool)
                    -> Result<Vec<QueryTerm>, ParserError>
     {
         let mut query_terms = vec![];
@@ -651,9 +654,9 @@ impl RelationWorker {
                   blocks_cuts: bool, assume_dyn: bool)
                   -> Result<Rule, ParserError>
     {
-        let post_head_terms: Vec<_> = terms.drain(1 ..).collect();
-
         let head = *terms.first().cloned().unwrap();
+        let post_head_terms: Vec<_> = terms.drain(1 .. ).collect();
+
         let tail = *post_head_terms.first().cloned().unwrap();
 
         if assume_dyn {
@@ -677,19 +680,23 @@ impl RelationWorker {
                       -> Result<TopLevel, ParserError>
     {
         match term {
-            Term::Clause(r, name, mut terms, fixity) =>
+            Term::Clause(r, name, terms, fixity) =>
                 if let Some(hook) = is_compile_time_hook(&name, &terms) {
                     let term = Term::Clause(r, name, terms, fixity);
                     let (hook, clause, queue) = self.setup_hook(hook, indices, term)?;
 
                     Ok(TopLevel::Declaration(Declaration::Hook(hook, clause, queue)))
                 } else if name.as_str() == "?-" {
-                    Ok(TopLevel::Query(try!(self.setup_query(indices, terms, blocks_cuts))))
+                    match setup_declaration(terms.iter().cloned().collect()) {
-                } else if name.as_str() == ":-" && terms.len() > 1 {
+                        Ok(decl) => return Ok(TopLevel::Declaration(decl)),
-                    Ok(TopLevel::Rule(try!(self.setup_rule(indices, terms, blocks_cuts, true))))
+                        _ => {}
+                    };
+                    
+                    Ok(TopLevel::Query(self.setup_query(indices, terms, blocks_cuts)?))
+                } else if name.as_str() == ":-" && terms.len() == 2 {
+                    Ok(TopLevel::Rule(self.setup_rule(indices, terms, blocks_cuts, true)?))
                 } else if name.as_str() == ":-" && terms.len() == 1 {
-                    let term = *terms.pop().unwrap();
+                    Ok(TopLevel::Declaration(setup_declaration(terms)?))
-                    Ok(TopLevel::Declaration(try!(setup_declaration(term))))
                 } else {
                     let term = Term::Clause(r, name, terms, fixity);
                     Ok(TopLevel::Fact(try!(self.setup_fact(term, true))))

src/prolog/read.rs

@@ -11,7 +11,7 @@ use prolog::machine::machine_state::MachineState;
 use std::collections::VecDeque;
 use std::io::Read;
 
-use readline_rs::readline::*;
+use readline_rs_compat::readline::*;
 
 type SubtermDeque = VecDeque<(usize, usize)>;
 
@@ -27,7 +27,6 @@ impl<'a> TermRef<'a> {
 }
 
 pub enum Input {
-    Quit,
     Clear,
     Batch,
     TermString(&'static str)
@@ -52,7 +51,7 @@ pub fn set_line_mode(mode: LineMode) {
 
 fn is_directive(buf: &str) -> bool {
     match buf {
-        "[user]" | "quit" | "clear" => true,
+        "?- [user]." | "?- [clear]." => true,
         _ => false
     }
 }
@@ -77,9 +76,6 @@ unsafe extern "C" fn bind_end_key(_: i32, _: i32) -> i32 {
 
 unsafe extern "C" fn bind_cr(_: i32, _: i32) -> i32 {    
     if END_OF_LINE {
-        println!("");
-        rl_done = 1;
-    } else {
         if let Some(buf) = rl_line_buffer_as_str() {
             if is_directive(buf) {
                 println!("");
@@ -88,6 +84,9 @@ unsafe extern "C" fn bind_cr(_: i32, _: i32) -> i32 {
             }
         }
         
+        println!("");
+        rl_done = 1;
+    } else {                
         insert_text_rl("\n");
     }
 
@@ -107,20 +106,46 @@ pub fn readline_initialize() {
     bind_keyseq_rl("\\C-d", bind_end_chord);
 }
 
-pub fn read_line(prompt: &str) -> Result<&'static str, SessionError> {
+pub fn read_batch(prompt: &str) -> Result<&'static str, SessionError> {
+    unsafe {
+        use std::ptr::null;
+        use std::mem;
+
+        // deactivate the startup hook that emits a "?- " to the
+        // beginning of the readline buffer.
+        let p: *const i8 = null();
+        rl_startup_hook = mem::transmute(p);
+    }
+    
     match readline_rl(prompt) {
         Some(input) => Ok(input),
         None => Err(SessionError::UserPrompt)
     }
 }
 
-pub fn toplevel_read_line() -> Result<Input, SessionError> {
+fn read_line(prompt: &str) -> Result<&'static str, SessionError> {    
-    let buffer = read_line("prolog> ")?;
+    match readline_rl(prompt) {
+        Some(input) => Ok(input),
+        None => Err(SessionError::UserPrompt)
+    }
+}
+
+unsafe extern "C" fn insert_query_prompt() -> i32 {
+    insert_text_rl("?- ");
+    0
+}
+
+pub fn toplevel_read_line() -> Result<Input, SessionError>
+{
+    unsafe {
+        rl_startup_hook = insert_query_prompt;
+    }
+    
+    let buffer = read_line("")?;
     
     Ok(match &*buffer.trim() {
-        "quit"   => Input::Quit,
+        "?- [clear]." => Input::Clear,
-        "clear"  => Input::Clear,
+        "?- [user]." => {
-        "[user]" => {
             println!("(type Enter + Ctrl-D to terminate the stream when finished)");
             Input::Batch
         },