extract teraron

5 files changed, 149 insertions, 72 deletions

diff --git a/crates/teraron/Cargo.toml b/crates/teraron/Cargo.toml
new file mode 100644
index 000000000..7ce9f1aa8
--- /dev/null
+++ b/crates/teraron/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "teraron"
+version = "0.0.1"
+authors = ["Aleksey Kladov <[email protected]>"]
+repository = "https://github.com/rust-analyzer/teraron"
+description = "Genrate Rust code from a .tera template and a .ron data"
+license = "MIT OR Apache-2.0"
+
+[dependencies]
+failure = "0.1.2"
+tera = "0.11.18"
+ron = "0.4.0"
+heck = "0.3.0"
diff --git a/crates/teraron/src/lib.rs b/crates/teraron/src/lib.rs
new file mode 100644
index 000000000..e464ea080
--- /dev/null
+++ b/crates/teraron/src/lib.rs
@@ -0,0 +1,109 @@
+//! A simple tool to generate rust code by passing a ron value
+//! to a tera template
+
+#[macro_use]
+extern crate failure;
+extern crate tera;
+extern crate ron;
+extern crate heck;
+
+use std::{
+    fs,
+    collections::HashMap,
+    path::Path,
+};
+
+use heck::{CamelCase, ShoutySnakeCase, SnakeCase};
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub enum Mode {
+    Overwrite,
+    Verify,
+}
+
+pub use Mode::*;
+
+/// A helper to update file on disk if it has changed.
+/// With verify = false,
+pub fn update(path: &Path, contents: &str, mode: Mode) -> Result<(), failure::Error> {
+    match fs::read_to_string(path) {
+        Ok(ref old_contents) if old_contents == contents => {
+            return Ok(());
+        }
+        _ => (),
+    }
+    if mode == Verify {
+        bail!("`{}` is not up-to-date", path.display());
+    }
+    eprintln!("updating {}", path.display());
+    fs::write(path, contents)?;
+    Ok(())
+}
+
+pub fn generate(
+    template: &Path,
+    src: &Path,
+    mode: Mode,
+) -> Result<(), failure::Error> {
+    assert_eq!(
+        template.extension().and_then(|it| it.to_str()), Some("tera"),
+        "template file must have .rs.tera extension",
+    );
+    let file_name = template.file_stem().unwrap().to_str().unwrap();
+    assert!(
+        file_name.ends_with(".rs"),
+        "template file must have .rs.tera extension",
+    );
+    let tgt = template.with_file_name(file_name);
+    let template = fs::read_to_string(template)?;
+    let src: ron::Value = {
+        let text = fs::read_to_string(src)?;
+        ron::de::from_str(&text)?
+    };
+    let content = render(&template, src)?;
+    update(
+        &tgt,
+        &content,
+        mode,
+    )
+}
+
+pub fn render(
+    template: &str,
+    src: ron::Value,
+) -> Result<String, failure::Error> {
+    let mut tera = mk_tera();
+    tera.add_raw_template("_src", template)
+        .map_err(|e| format_err!("template parsing error: {:?}", e))?;
+    let res = tera.render("_src", &src)
+        .map_err(|e| format_err!("template rendering error: {:?}", e))?;
+    return Ok(res);
+}
+
+fn mk_tera() -> tera::Tera {
+    let mut res = tera::Tera::default();
+    res.register_filter("camel", |arg, _| {
+        Ok(arg.as_str().unwrap().to_camel_case().into())
+    });
+    res.register_filter("snake", |arg, _| {
+        Ok(arg.as_str().unwrap().to_snake_case().into())
+    });
+    res.register_filter("SCREAM", |arg, _| {
+        Ok(arg.as_str().unwrap().to_shouty_snake_case().into())
+    });
+    res.register_function("concat", Box::new(concat));
+    res
+}
+
+fn concat(args: HashMap<String, tera::Value>) -> tera::Result<tera::Value> {
+    let mut elements = Vec::new();
+    for &key in ["a", "b", "c"].iter() {
+        let val = match args.get(key) {
+            Some(val) => val,
+            None => continue,
+        };
+        let val = val.as_array().unwrap();
+        elements.extend(val.iter().cloned());
+    }
+    Ok(tera::Value::Array(elements))
+}
diff --git a/crates/tools/Cargo.toml b/crates/tools/Cargo.toml
index e2fecc60d..ffd0ab1a5 100644
--- a/crates/tools/Cargo.toml
+++ b/crates/tools/Cargo.toml
@@ -6,10 +6,8 @@ authors = ["Aleksey Kladov <[email protected]>"]
 publish = false
 
 [dependencies]
-ron = "0.3.0"
+teraron = { path = "../teraron"}
 walkdir = "2.1.3"
 itertools = "0.7.8"
-tera = "0.11"
 clap = "2.32.0"
 failure = "0.1.1"
-heck = "0.3.0"
diff --git a/crates/tools/src/lib.rs b/crates/tools/src/lib.rs
index 5d5d372bb..63ede5315 100644
--- a/crates/tools/src/lib.rs
+++ b/crates/tools/src/lib.rs
@@ -1,25 +1,18 @@
 extern crate itertools;
 #[macro_use]
 extern crate failure;
-extern crate heck;
-extern crate ron;
-extern crate tera;
 
-use heck::{CamelCase, ShoutySnakeCase, SnakeCase};
 use itertools::Itertools;
 use std::{
-    collections::HashMap,
     fs,
     path::{Path, PathBuf},
 };
 
 pub type Result<T> = ::std::result::Result<T, failure::Error>;
 
-const GRAMMAR: &str = "ra_syntax/src/grammar.ron";
-pub const SYNTAX_KINDS: &str = "ra_syntax/src/syntax_kinds/generated.rs";
-pub const SYNTAX_KINDS_TEMPLATE: &str = "ra_syntax/src/syntax_kinds/generated.rs.tera";
-pub const AST: &str = "ra_syntax/src/ast/generated.rs";
-pub const AST_TEMPLATE: &str = "ra_syntax/src/ast/generated.rs.tera";
+pub const GRAMMAR: &str = "ra_syntax/src/grammar.ron";
+pub const SYNTAX_KINDS: &str = "ra_syntax/src/syntax_kinds/generated.rs.tera";
+pub const AST: &str = "ra_syntax/src/ast/generated.rs.tera";
 
 #[derive(Debug)]
 pub struct Test {
@@ -76,43 +69,6 @@ pub fn update(path: &Path, contents: &str, verify: bool) -> Result<()> {
     Ok(())
 }
 
-pub fn render_template(template: &Path) -> Result<String> {
-    let grammar: ron::value::Value = {
-        let text = fs::read_to_string(project_root().join(GRAMMAR))?;
-        ron::de::from_str(&text)?
-    };
-    let template = fs::read_to_string(template)?;
-    let mut tera = tera::Tera::default();
-    tera.add_raw_template("grammar", &template)
-        .map_err(|e| format_err!("template error: {:?}", e))?;
-    tera.register_function("concat", Box::new(concat));
-    tera.register_filter("camel", |arg, _| {
-        Ok(arg.as_str().unwrap().to_camel_case().into())
-    });
-    tera.register_filter("snake", |arg, _| {
-        Ok(arg.as_str().unwrap().to_snake_case().into())
-    });
-    tera.register_filter("SCREAM", |arg, _| {
-        Ok(arg.as_str().unwrap().to_shouty_snake_case().into())
-    });
-    let ret = tera
-        .render("grammar", &grammar)
-        .map_err(|e| format_err!("template error: {:?}", e))?;
-    return Ok(ret);
-
-    fn concat(args: HashMap<String, tera::Value>) -> tera::Result<tera::Value> {
-        let mut elements = Vec::new();
-        for &key in ["a", "b", "c"].iter() {
-            let val = match args.get(key) {
-                Some(val) => val,
-                None => continue,
-            };
-            let val = val.as_array().unwrap();
-            elements.extend(val.iter().cloned());
-        }
-        Ok(tera::Value::Array(elements))
-    }
-}
 
 pub fn project_root() -> PathBuf {
     Path::new(&std::env::var("CARGO_MANIFEST_DIR").unwrap())
diff --git a/crates/tools/src/main.rs b/crates/tools/src/main.rs
index b662d78df..1bbc43123 100644
--- a/crates/tools/src/main.rs
+++ b/crates/tools/src/main.rs
@@ -3,6 +3,7 @@ extern crate clap;
 extern crate failure;
 extern crate tools;
 extern crate walkdir;
+extern crate teraron;
 
 use clap::{App, Arg, SubCommand};
 use std::{
@@ -12,9 +13,9 @@ use std::{
     process::Command,
 };
 use tools::{
-    collect_tests, project_root, render_template, update, Result, Test, AST, AST_TEMPLATE,
-    SYNTAX_KINDS, SYNTAX_KINDS_TEMPLATE,
+    collect_tests, project_root, Result, Test, AST, SYNTAX_KINDS, GRAMMAR,
 };
+use teraron::{Mode, Verify, Overwrite};
 
 const GRAMMAR_DIR: &str = "./crates/ra_syntax/src/grammar";
 const INLINE_TESTS_DIR: &str = "./crates/ra_syntax/tests/data/parser/inline";
@@ -32,35 +33,35 @@ fn main() -> Result<()> {
         .subcommand(SubCommand::with_name("gen-tests"))
         .subcommand(SubCommand::with_name("install-code"))
         .get_matches();
+    let mode = if matches.is_present("verify") {
+        Verify
+    } else {
+        Overwrite
+    };
     match matches.subcommand() {
         ("install-code", _) => install_code_extension()?,
-        (name, Some(matches)) => run_gen_command(name, matches.is_present("verify"))?,
-        _ => unreachable!(),
-    }
-    Ok(())
-}
-
-fn run_gen_command(name: &str, verify: bool) -> Result<()> {
-    match name {
-        "gen-kinds" => {
-            update(
-                &project_root().join(SYNTAX_KINDS),
-                &render_template(&project_root().join(SYNTAX_KINDS_TEMPLATE))?,
-                verify,
+        ("gen-tests", _) => gen_tests(mode)?,
+        ("gen-kinds", _) => {
+            let grammar = project_root().join(GRAMMAR);
+            let syntax_kinds = project_root().join(SYNTAX_KINDS);
+            let ast = project_root().join(AST);
+            teraron::generate(
+                &syntax_kinds,
+                &grammar,
+                mode,
             )?;
-            update(
-                &project_root().join(AST),
-                &render_template(&project_root().join(AST_TEMPLATE))?,
-                verify,
+            teraron::generate(
+                &ast,
+                &grammar,
+                mode,
             )?;
         }
-        "gen-tests" => gen_tests(verify)?,
         _ => unreachable!(),
     }
     Ok(())
 }
 
-fn gen_tests(verify: bool) -> Result<()> {
+fn gen_tests(mode: Mode) -> Result<()> {
     let tests = tests_from_dir(Path::new(GRAMMAR_DIR))?;
 
     let inline_tests_dir = Path::new(INLINE_TESTS_DIR);
@@ -83,7 +84,7 @@ fn gen_tests(verify: bool) -> Result<()> {
                 inline_tests_dir.join(file_name)
             }
         };
-        update(&path, &test.text, verify)?;
+        teraron::update(&path, &test.text, mode)?;
     }
     Ok(())
 }