readd executable parser

parser/examples/parser.rs

@@ -0,0 +1,68 @@
+// Copyright (C) 2019-2021 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use leo_ast::Ast;
+use leo_parser::errors::SyntaxError;
+use std::{env, fs, path::Path};
+
+fn to_leo_tree(filepath: &Path) -> Result<String, SyntaxError> {
+    // Loads the Leo code as a string from the given file path.
+    let program_filepath = filepath.to_path_buf();
+    let program_string = fs::read_to_string(&program_filepath).expect("failed to open input file");
+
+    // Parses the Leo file and constructs an ast.
+    let ast = leo_parser::parse_ast(filepath.to_str().unwrap(), &program_string)?;
+
+    let serialized_leo_ast = Ast::to_json_string(&ast).expect("serialization failed");
+
+    Ok(serialized_leo_ast)
+}
+
+fn main() -> Result<(), SyntaxError> {
+    // Parse the command-line arguments as strings.
+    let cli_arguments = env::args().collect::<Vec<String>>();
+
+    // Check that the correct number of command-line arguments were passed in.
+    if cli_arguments.len() < 2 || cli_arguments.len() > 3 {
+        eprintln!("Warning - an invalid number of command-line arguments were provided.");
+        println!(
+            "\nCommand-line usage:\n\n\tleo_ast {{PATH/TO/INPUT_FILENAME}}.leo {{PATH/TO/OUTPUT_DIRECTORY (optional)}}\n"
+        );
+        return Ok(()); // Exit innocently
+    }
+
+    // Construct the input filepath.
+    let input_filepath = Path::new(&cli_arguments[1]);
+
+    // Construct the serialized syntax tree.
+    let serialized_leo_tree = to_leo_tree(&input_filepath)?;
+    println!("{}", serialized_leo_tree);
+
+    // Determine the output directory.
+    let output_directory = match cli_arguments.len() == 3 {
+        true => format!(
+            "{}/{}.json",
+            cli_arguments[2],
+            input_filepath.file_stem().unwrap().to_str().unwrap()
+        ),
+        false => format!("./{}.json", input_filepath.file_stem().unwrap().to_str().unwrap()),
+    };
+
+    // Write the serialized syntax tree to the output directory.
+    fs::write(Path::new(&output_directory), serialized_leo_tree).expect("failed to write output");
+
+    Ok(())
+}