Parse simple number literal

Cargo.lock

@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "ahash"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e8fd72866655d1904d6b0997d0b07ba561047d070fbe29de039031c641b61217"
+dependencies = [
+ "const-random",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.66"
@@ -25,6 +34,21 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "chumsky"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d02796e4586c6c41aeb68eae9bfb4558a522c35f1430c14b40136c3706e09e4"
+dependencies = [
+ "ahash",
+]
+
 [[package]]
 name = "clap"
 version = "4.0.26"
@@ -62,6 +86,45 @@ dependencies = [
  "os_str_bytes",
 ]
 
+[[package]]
+name = "const-random"
+version = "0.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "368a7a772ead6ce7e1de82bfb04c485f3db8ec744f72925af5735e29a22cc18e"
+dependencies = [
+ "const-random-macro",
+ "proc-macro-hack",
+]
+
+[[package]]
+name = "const-random-macro"
+version = "0.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9d7d6ab3c3a2282db210df5f02c4dab6e0a7057af0fb7ebd4070f30fe05c0ddb"
+dependencies = [
+ "getrandom",
+ "once_cell",
+ "proc-macro-hack",
+ "tiny-keccak",
+]
+
+[[package]]
+name = "crunchy"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
+
+[[package]]
+name = "getrandom"
+version = "0.2.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c05aeb6a22b8f62540c194aac980f2115af067bfe15a0734d7277a768d396b31"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "heck"
 version = "0.4.0"
@@ -119,6 +182,12 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "proc-macro-hack"
+version = "0.5.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dbf0c48bc1d91375ae5c3cd81e3722dff1abcf81a30960240640d223f59fe0e5"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.47"
@@ -159,6 +228,7 @@ name = "tada"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "chumsky",
  "clap",
 ]
 
@@ -171,6 +241,15 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "tiny-keccak"
+version = "2.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c9d3793400a45f954c52e73d068316d76b6f4e36977e3fcebb13a2721e80237"
+dependencies = [
+ "crunchy",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.5"
@@ -183,6 +262,12 @@ version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
+
 [[package]]
 name = "winapi"
 version = "0.3.9"

Cargo.toml

@@ -5,4 +5,5 @@ edition = "2021"
 
 [dependencies]
 anyhow = "1.0.66"
+chumsky = "0.8.0"
 clap = { version = "4.0.26", features = ["derive", "deprecated"] }

src/main.rs

@@ -1,9 +1,11 @@
 use std::fs;
 use std::path::PathBuf;
 
+use chumsky::Parser as _;
 use clap::Parser;
 
 mod builtin;
+mod parser;
 mod table;
 mod value;
 
@@ -25,9 +27,14 @@ fn main() -> anyhow::Result<()> {
     match args.command {
         Command::Parse { file } => {
             let content = fs::read_to_string(&file)?;
-            print!("{content}");
+            match parser::parser().parse(&content as &str) {
-            if !content.ends_with('\n') {
+                Ok(lit) => println!("Successful parse: {lit:#?}"),
-                println!();
+                Err(errs) => {
+                    println!("Parsing failed");
+                    for err in errs {
+                        println!("{err:?}");
+                    }
+                }
             }
         }
     }

src/parser.rs

@@ -0,0 +1,37 @@
+use chumsky::prelude::*;
+
+#[derive(Debug)]
+pub enum Lit {
+    Num(i64),
+}
+
+fn lit_num() -> impl Parser<char, i64, Error = Simple<char>> {
+    let sign = just('+')
+        .or(just('-'))
+        .or_not()
+        .map(|s| if s == Some('-') { -1_i128 } else { 1_i128 });
+
+    let digits = text::int(10);
+
+    sign.then(digits).try_map(|(sign, digits), span| {
+        // u64::MIN and u32::MAX have 19 digits in base 10
+        if digits.len() > 19 {
+            return Err(Simple::custom(span, "number out of range"));
+        }
+
+        let number = sign * digits.parse::<i128>().unwrap();
+        if number < i64::MIN.into() || number > u64::MAX.into() {
+            return Err(Simple::custom(span, "number out of range"));
+        }
+
+        Ok(number as i64)
+    })
+}
+
+fn lit() -> impl Parser<char, Lit, Error = Simple<char>> {
+    lit_num().map(Lit::Num)
+}
+
+pub fn parser() -> impl Parser<char, Lit, Error = Simple<char>> {
+    lit().padded().then_ignore(end())
+}