DEV: Adds a Repl for ucg.

Uses a StatementAccumulator to handle the accumulation of lines
until a line terminated with a statement is encountered.

Fixes #41

Cargo.lock

@@ -40,7 +40,7 @@ name = "atty"
 version = "0.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "termion 1.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -52,7 +52,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "backtrace-sys 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-demangle 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -63,7 +63,7 @@ version = "0.1.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.22 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -138,7 +138,7 @@ name = "dirs"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_users 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -203,7 +203,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "libc"
-version = "0.2.46"
+version = "0.2.55"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -211,16 +211,36 @@ name = "linked-hash-map"
 version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "log"
+version = "0.4.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "memchr"
 version = "2.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "nix"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc 1.0.22 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
+ "void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "nodrop"
 version = "0.1.13"
@@ -248,7 +268,7 @@ version = "0.4.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "fuchsia-zircon 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -316,6 +336,22 @@ name = "rustc-demangle"
 version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "rustyline"
+version = "4.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "dirs 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 2.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nix 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-segmentation 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "utf8parse 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "ryu"
 version = "0.2.5"
@@ -397,7 +433,7 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -406,7 +442,7 @@ name = "termion"
 version = "1.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_syscall 0.1.40 (registry+https://github.com/rust-lang/crates.io-index)",
  "redox_termios 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -451,6 +487,7 @@ dependencies = [
  "clap 2.26.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "dirs 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustyline 4.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_yaml 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "simple-error 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -480,6 +517,11 @@ name = "utf8-ranges"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "utf8parse"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "vec_map"
 version = "0.8.1"
@@ -490,6 +532,11 @@ name = "version_check"
 version = "0.1.5"
 source = "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"
+
 [[package]]
 name = "walkdir"
 version = "2.2.7"
@@ -578,9 +625,11 @@ dependencies = [
 "checksum itoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "5adb58558dcd1d786b5f0bd15f3226ee23486e24b7b58304b60f64dc68e62606"
 "checksum kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7507624b29483431c0ba2d82aece8ca6cdba9382bff4ddd0f7490560c056098d"
 "checksum lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a374c89b9db55895453a74c1e38861d9deec0b01b405a82516e9d5de4820dea1"
-"checksum libc 0.2.46 (registry+https://github.com/rust-lang/crates.io-index)" = "023a4cd09b2ff695f9734c1934145a315594b7986398496841c7031a5a1bbdbd"
+"checksum libc 0.2.55 (registry+https://github.com/rust-lang/crates.io-index)" = "42914d39aad277d9e176efbdad68acb1d5443ab65afe0e0e4f0d49352a950880"
 "checksum linked-hash-map 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "70fb39025bc7cdd76305867c4eccf2f2dcf6e9a57f5b21a93e1c2d86cd03ec9e"
+"checksum log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "c84ec4b527950aa83a329754b01dbe3f58361d1c5efacd1f6d68c494d08a17c6"
 "checksum memchr 2.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "db4c41318937f6e76648f42826b1d9ade5c09cafb5aef7e351240a70f39206e9"
+"checksum nix 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)" = "46f0f3210768d796e8fa79ec70ee6af172dacbe7147f5e69be5240a47778302b"
 "checksum nodrop 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)" = "2f9667ddcc6cc8a43afc9b7917599d7216aa09c463919ea32c59ed6cac8bc945"
 "checksum proc-macro2 0.4.24 (registry+https://github.com/rust-lang/crates.io-index)" = "77619697826f31a02ae974457af0b29b723e5619e113e9397b8b82c6bd253f09"
 "checksum quote 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)" = "53fa22a1994bd0f9372d7a816207d8a2677ad0325b073f5c5332760f0fb62b5c"
@@ -593,6 +642,7 @@ dependencies = [
 "checksum regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "37e7cbbd370869ce2e8dff25c7018702d10b21a20ef7135316f8daecd6c25b7f"
 "checksum regex-syntax 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "4e47a2ed29da7a9e1960e1639e7a982e6edc6d49be308a3b02daf511504a16d1"
 "checksum rustc-demangle 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "bcfe5b13211b4d78e5c2cadfebd7769197d95c639c35a50057eb4c05de811395"
+"checksum rustyline 4.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0f47ea1ceb347d2deae482d655dc8eef4bd82363d3329baffa3818bd76fea48b"
 "checksum ryu 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)" = "e7c066b8e2923f05d4718a06d2622f189ff362bc642bfade6c6629f0440f3827"
 "checksum same-file 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8f20c4be53a8a1ff4c1f1b2bd14570d2f634628709752f0702ecdd2b3f9a5267"
 "checksum scoped_threadpool 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "1d51f5df5af43ab3f1360b429fa5e0152ac5ce8c0bd6485cae490332e96846a8"
@@ -613,8 +663,10 @@ dependencies = [
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
 "checksum utf8-ranges 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "796f7e48bef87609f7ade7e06495a87d5cd06c7866e6a5cbfceffc558a243737"
+"checksum utf8parse 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "8772a4ccbb4e89959023bc5b7cb8623a795caa7092d99f3aa9501b9484d4557d"
 "checksum vec_map 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "05c78687fb1a80548ae3250346c3db86a80a7cdd77bda190189f2d0a0987c81a"
 "checksum version_check 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "914b1a6776c4c929a602fafd8bc742e06365d4bcbe48c30f9cca5824f70dc9dd"
+"checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum walkdir 2.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "9d9d7ed3431229a144296213105a390676cc49c9b6a72bd19f3176c98e129fa1"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "773ef9dcc5f24b7d850d0ff101e542ff24c3b090a9768e03ff889fdef41f00fd"

Cargo.toml

@@ -30,6 +30,7 @@ base64 = "0.10.0"
 regex = "1"
 dirs = "1.0.4"
 unicode-segmentation = "1.2.1"
+rustyline = "4.1.0"
 
 [build-dependencies]
 walkdir = "2.2.7"

src/build/mod.rs

@@ -302,7 +302,7 @@ impl<'a> FileBuilder<'a> {
         Ok(())
     }
 
-    fn eval_input(&mut self, input: OffsetStrIter) -> Result<Rc<Val>, Box<dyn Error>> {
+    pub fn eval_input(&mut self, input: OffsetStrIter) -> Result<Rc<Val>, Box<dyn Error>> {
         match parse(input.clone(), None) {
             Ok(stmts) => {
                 //panic!("Successfully parsed {}", input);

src/io/mod.rs

@@ -0,0 +1,58 @@
+// Copyright 2019 Jeremy Wall
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+use std::convert::Into;
+
+/// Accumulates lines and tells you when a ucg Statement has been read.
+pub struct StatementAccumulator {
+    acc: Vec<String>,
+}
+
+impl StatementAccumulator {
+    /// Constructs a StatementAccumulator ready for use.
+    pub fn new() -> Self {
+        Self { acc: Vec::new() }
+    }
+
+    /// Tells you if the latest line ends in the statement terminator.
+    ///
+    /// Returns None if it wasn't a terminated statement and leaves the
+    /// accumulated lines alone.
+    ///
+    /// Returns Some(String) with the terminated statement if it was a
+    /// terminated statement and drains the accumulated statements out.
+    pub fn get_statement(&mut self) -> Option<String> {
+        if let Some(l) = self.acc.last() {
+            if l.trim_end().ends_with(";") {
+                let mut stmt = self.acc.drain(0..).fold(String::new(), |mut acc, s| {
+                    acc.push_str(&s);
+                    acc.push_str("\n");
+                    acc
+                });
+                stmt.shrink_to_fit();
+                return Some(stmt);
+            }
+        }
+        None
+    }
+
+    /// Pushes a line into the Statement Accumulator. Assumes that the
+    /// new line has already been trimmed. get_statement will reintroduce
+    /// the new lines.
+    pub fn push<S: Into<String>>(&mut self, line: S) {
+        self.acc.push(line.into());
+    }
+}
+
+#[cfg(test)]
+mod test;

src/io/test.rs

@@ -0,0 +1,40 @@
+// Copyright 2019 Jeremy Wall
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+use crate::io::*;
+
+#[test]
+fn test_line_accumulator_single_line_stmt() {
+    let test_line = "1 + 1;";
+    let mut expected = String::new();
+    expected.push_str(test_line);
+    expected.push_str("\n");
+    let mut acc = StatementAccumulator::new();
+    acc.push(test_line);
+    assert_eq!(acc.get_statement().unwrap(), expected);
+}
+
+#[test]
+fn test_line_accumulator_multi_line_stmt() {
+    let test_line1 = "1 ";
+    let test_line2 = "+ 1;";
+    let mut expected = String::new();
+    expected.push_str(test_line1);
+    expected.push_str("\n");
+    expected.push_str(test_line2);
+    expected.push_str("\n");
+    let mut acc = StatementAccumulator::new();
+    acc.push(test_line1);
+    acc.push(test_line2);
+    assert_eq!(acc.get_statement().unwrap(), expected);
+}

src/lib.rs

@@ -38,6 +38,7 @@ pub mod tokenizer;
 pub mod build;
 pub mod convert;
 pub mod error;
+pub mod io;
 pub mod iter;
 pub mod parse;
 

src/main.rs

@@ -14,6 +14,7 @@
 #[macro_use]
 extern crate clap;
 extern crate dirs;
+extern crate rustyline;
 extern crate ucglib;
 
 use std::cell::RefCell;
@@ -47,6 +48,9 @@ fn do_flags<'a, 'b>() -> clap::App<'a, 'b> {
              (@arg target: --format +takes_value "Output type. (flags, json, env, exec) defaults to json.")
              (@arg INPUT: "ucg file to use as context for the expression.")
             )
+            (@subcommand repl =>
+                (about: "Start the ucg repl for interactive evaluation.")
+            )
             (@subcommand build =>
              (about: "Build a list of ucg files.")
              (@arg recurse: -r "Whether we should recurse in directories or not.")
@@ -509,6 +513,78 @@ fn env_help() {
     );
 }
 
+fn do_repl(
+    import_paths: &Vec<PathBuf>,
+    cache: Rc<RefCell<Cache>>,
+) -> std::result::Result<(), Box<dyn Error>> {
+    let config = rustyline::Config::builder();
+    let mut editor = rustyline::Editor::<()>::with_config(
+        config
+            .history_ignore_space(true)
+            .history_ignore_dups(false)
+            .build(),
+    );
+    let path_home = dirs::home_dir().unwrap_or(std::env::temp_dir());
+    let config_home = std::env::var("XDG_CACHE_HOME")
+        .unwrap_or_else(|_| format!("{}/.cache", path_home.to_string_lossy()));
+    let mut config_home = PathBuf::from(config_home);
+    config_home.push("ucg");
+    config_home.push("line_hist");
+    if editor.load_history(&config_home).is_err() {
+        eprintln!(
+            "No history file {} Continuing without history.",
+            config_home.to_string_lossy()
+        );
+        // introduce a scope so the file will get automatically closed after
+        {
+            let base_dir = config_home.parent().unwrap();
+            if !base_dir.exists() {
+                if let Err(e) = std::fs::create_dir_all(base_dir) {
+                    eprintln!("{}", e);
+                }
+            }
+            if let Err(e) = std::fs::File::create(&config_home) {
+                eprintln!("{}", e);
+            }
+        }
+    }
+    let mut builder = build::FileBuilder::new(std::env::current_dir()?, import_paths, cache);
+    // loop
+    let mut lines = ucglib::io::StatementAccumulator::new();
+    loop {
+        // print prompt
+        lines.push(editor.readline("ucg> ")?);
+        // check to see if that line is a statement
+        loop {
+            // read a statement
+            if let Some(stmt) = lines.get_statement() {
+                // if it is then
+                // eval statement
+                match builder.eval_string(&stmt) {
+                    // print the result
+                    Err(e) => eprintln!("{}", e),
+                    Ok(v) => {
+                        println!("{}", v);
+                        editor.history_mut().add(stmt);
+                        editor.save_history(&config_home)?;
+                    }
+                }
+                // start loop over at prompt.
+                break;
+            }
+            // if not then keep accumulating lines without a prompt
+            lines.push(editor.readline(">>   ")?);
+        }
+    }
+}
+
+fn repl(import_paths: &Vec<PathBuf>, cache: Rc<RefCell<Cache>>) {
+    if let Err(e) = do_repl(import_paths, cache) {
+        eprintln!("{}", e);
+        process::exit(1);
+    }
+}
+
 fn main() {
     let mut app = do_flags();
     let app_matches = app.clone().get_matches();
@@ -546,6 +622,8 @@ fn main() {
         importers_command(&registry)
     } else if let Some(_) = app_matches.subcommand_matches("env") {
         env_help()
+    } else if let Some(_) = app_matches.subcommand_matches("repl") {
+        repl(&import_paths, cache)
     } else if let Some(matches) = app_matches.subcommand_matches("fmt") {
         if let Err(e) = fmt_command(matches) {
             eprintln!("{}", e);