Debug button to show Datalog AST

.gitignore

@@ -9,3 +9,6 @@ pkg/
 /mocha-setup.js
 /test-loader.js
 /test.html
+
+# auto-generated AST typedefs
+/crates/percival/bindings

Makefile

@@ -0,0 +1,22 @@
+# Filetypes
+RUST = $(shell find crates -name '*.rs')
+PATCHES = $(shell find patches -name '*.patch')
+
+# Repeated paths
+percival_wasm_pkg = crates/percival-wasm/pkg
+percival_bindings = crates/percival/bindings
+
+node_modules: package.json package-lock.json $(PATCHES) $(percival_wasm_pkg)
+	npm install
+
+crates/percival-wasm/pkg: $(RUST)
+	#	Build WASM
+	wasm-pack build --target web crates/percival-wasm
+	# Build AST types
+	cargo test ast::export_bindings
+	mkdir -p $(percival_wasm_pkg)/ast
+	for ts in $(percival_bindings)/* ; do \
+		cp $$ts $(percival_wasm_pkg)/ast/"$$(basename "$${ts%.ts}.d.ts")" ; \
+	done
+	# Patch WASM types to use AST types
+	sed -i '' -e 's~ast(): any~ast(): import("./ast/Program").Program | undefined~' $(percival_wasm_pkg)/percival_wasm.d.ts

README.md

@@ -40,11 +40,12 @@ information below is technical documentation intended for contributors.
 Building Percival from scratch requires [Node v16+](https://nodejs.org/en/),
 [NPM v8+](https://www.npmjs.com/), [Rust 1.56+](https://www.rust-lang.org/),
 [Cargo](https://crates.io/), and
-[Wasm-Pack](https://rustwasm.github.io/wasm-pack/) installed on your machine. To
-build the Rust/WebAssembly portion of the project, use the command:
+[Wasm-Pack](https://rustwasm.github.io/wasm-pack/) installed on your machine.
+
+To build the Rust/WebAssembly portion of the project, use the command:
 
 ```shell
-wasm-pack build --target web crates/percival-wasm
+make crates/percival-wasm/pkg
 ```
 
 Next, run `npm install` to install JavaScript dependencies, then run the

crates/percival-cli/src/main.rs

@@ -1,15 +1,25 @@
 //! Crate containing code for the `percival-cli` binary.
 
+use std::error::Error;
 use std::{
     fs::read_to_string,
     io::{self, Read, Write},
     path::PathBuf,
     process::{self, Command, Stdio},
 };
 
-use clap::Parser;
+use clap::{ArgEnum, Parser};
 
-use percival::{codegen::compile, errors::format_errors, parser::Grammar};
+use percival::{
+    codegen_js::compile as compile_js, codegen_json::compile as compile_json,
+    errors::format_errors, parser::Grammar,
+};
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, ArgEnum, Debug)]
+enum Emitter {
+    JS,
+    JSON,
+}
 
 /// Convenience CLI for testing the Percival language compiler.
 #[derive(Parser, Debug)]
@@ -22,6 +32,9 @@ struct Opt {
     /// Runs prettier and bat on the output.
     #[clap(short, long)]
     format: bool,
+
+    #[clap(short, long, arg_enum, default_value_t = Emitter::JS)]
+    emit: Emitter,
 }
 
 /// Run the main program.
@@ -49,7 +62,12 @@ fn main() {
         }
     };
 
-    match compile(&prog) {
+    let emitted: Result<String, Box<dyn Error>> = match opt.emit {
+        Emitter::JS => compile_js(&prog).map_err(|err| err.into()),
+        Emitter::JSON => compile_json(&prog).map_err(|err| err.into()),
+    };
+
+    match emitted {
         Ok(js) => {
             if !opt.format {
                 println!("{}", js);

crates/percival-wasm/Cargo.toml

@@ -13,7 +13,7 @@ default = ["console_error_panic_hook"]
 [dependencies]
 console_error_panic_hook = { version = "0.1", optional = true }
 percival = { path = "../percival" }
-wasm-bindgen = "0.2"
+wasm-bindgen = { version = "0.2", features = ["serde-serialize"] }
 yansi = "0.5.0"
 
 [dev-dependencies]

crates/percival-wasm/src/lib.rs

@@ -5,7 +5,7 @@
 use wasm_bindgen::prelude::*;
 use yansi::Paint;
 
-use percival::{ast::Program, codegen, errors::format_errors, parser::Grammar};
+use percival::{ast::Program, codegen_js, errors::format_errors, parser::Grammar};
 
 /// Set a panic listener to display better error messages.
 #[wasm_bindgen(start)]
@@ -36,7 +36,7 @@ pub fn compile(src: &str) -> CompilerResult {
             .parse(&src[..])
             .map_err(|err| format_errors(&src[..], err))
             .and_then(|prog| {
-                let js = codegen::compile(&prog)
+                let js = codegen_js::compile(&prog)
                     .map_err(|err| format!("{} {}", Paint::red("Error:"), err))?;
                 Ok((prog, js))
             })
@@ -54,6 +54,22 @@ impl CompilerResult {
         self.0.as_ref().ok().map(|(_, js)| js.clone())
     }
 
+    /// Returns the AST of the program's source.
+    pub fn ast(&self) -> JsValue {
+        self.0
+            .as_ref()
+            .ok()
+            .map(|(prog, _)| match JsValue::from_serde(prog) {
+                Ok(ast) => ast,
+                Err(err) => {
+                    // XX: wasm-bindgen claims to have errors, but doesn't
+                    eprintln!("{} {}", Paint::red("Error:"), err);
+                    JsValue::UNDEFINED
+                }
+            })
+            .unwrap_or(JsValue::UNDEFINED)
+    }
+
     /// Returns the names of relations that are dependencies of this program.
     pub fn deps(&self) -> Option<Vec<JsValue>> {
         self.0.as_ref().ok().map(|(prog, _)| {

crates/percival/Cargo.toml

@@ -9,6 +9,9 @@ ariadne = "0.1.3"
 chumsky = "0.7.0"
 rpds = "0.11.0"
 thiserror = "1.0.30"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+ts-rs = "6.1"
 
 [dev-dependencies]
 maplit = "1.0.2"

crates/percival/src/ast.rs

@@ -1,9 +1,12 @@
 //! Abstract syntax tree definitions for the Percival language.
 
+use serde::Serialize;
 use std::collections::{BTreeMap, BTreeSet};
+use ts_rs::TS;
 
 /// A program translation unit in the Percival language.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub struct Program {
     /// Rules that make up the program.
     pub rules: Vec<Rule>,
@@ -12,7 +15,8 @@ pub struct Program {
 }
 
 /// Represents a single Horn clause.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub struct Rule {
     /// Head or implicand of the Horn clause.
     pub goal: Fact,
@@ -21,7 +25,8 @@ pub struct Rule {
 }
 
 /// An element of the right-hand side of a rule.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub enum Clause {
     /// Relational assumption in the rule.
     Fact(Fact),
@@ -32,7 +37,8 @@ pub enum Clause {
 }
 
 /// Literal part of a Horn clause, written in terms of relations.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub struct Fact {
     /// Name of the relation being referenced.
     pub name: String,
@@ -41,7 +47,8 @@ pub struct Fact {
 }
 
 /// A bound or unbound value assigned to part of a relation.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub enum Value {
     /// A simple identifier, which can be either bound or unbound.
     Id(String),
@@ -54,7 +61,8 @@ pub enum Value {
 }
 
 /// Literal values supported by the Percival grammar.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub enum Literal {
     /// A standard floating-point number literal.
     Number(String),
@@ -65,7 +73,8 @@ pub enum Literal {
 }
 
 /// An aggregate operation over stratified dependency relations.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub struct Aggregate {
     /// Name of the aggregate operator, such as `min` or `sum`.
     pub operator: String,
@@ -76,7 +85,8 @@ pub struct Aggregate {
 }
 
 /// An external import from a static JSON dataset.
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, TS)]
+#[ts(export)]
 pub struct Import {
     /// Name of the relation being imported.
     pub name: String,

crates/percival/src/codegen_json.rs

@@ -0,0 +1,10 @@
+//! JSON AST emitter (is this really needed??)
+
+use serde_json::to_string_pretty;
+
+use crate::ast::Program;
+
+/// Generates a JSON representation of the program AST.
+pub fn compile(prog: &Program) -> Result<String, serde_json::Error> {
+    to_string_pretty(prog)
+}

crates/percival/src/lib.rs

@@ -4,6 +4,7 @@
 #![warn(missing_docs)]
 
 pub mod ast;
-pub mod codegen;
+pub mod codegen_js;
+pub mod codegen_json;
 pub mod errors;
 pub mod parser;