Update the lrlex tool to read %grmtools section, emit diagnostics.

Author: ratmice

lrlex/src/main.rs

@@ -1,16 +1,38 @@
 use getopts::Options;
 use std::{
     env,
+    error::Error,
+    fmt,
     fs::File,
     io::{stderr, stdin, Read, Write},
     path::Path,
     process,
-    str::FromStr,
 };
 
-use cfgrammar::{newlinecache::NewlineCache, Spanned};
-use lrlex::{DefaultLexerTypes, LRNonStreamingLexerDef, LexerDef};
-use lrpar::{Lexeme, Lexer};
+use cfgrammar::header::{GrmtoolsSectionParser, HeaderValue};
+use lrlex::{DefaultLexerTypes, LRNonStreamingLexerDef, LexFlags, LexerDef, LexerKind};
+use lrpar::{
+    diagnostics::{DiagnosticFormatter, SpannedDiagnosticFormatter},
+    Lexeme, Lexer,
+};
+
+const ERROR: &str = "[Error]";
+
+/// A string which uses `Display` for it's `Debug` impl.
+struct ErrorString(String);
+impl fmt::Display for ErrorString {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let ErrorString(s) = self;
+        write!(f, "{}", s)
+    }
+}
+impl fmt::Debug for ErrorString {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let ErrorString(s) = self;
+        write!(f, "{}", s)
+    }
+}
+impl Error for ErrorString {}
 
 fn usage(prog: &str, msg: &str) {
     let path = Path::new(prog);
@@ -42,43 +64,80 @@ fn read_file(path: &str) -> String {
     s
 }
 
-fn main() {
+fn main() -> Result<(), Box<dyn Error>> {
     let args: Vec<String> = env::args().collect();
     let prog = args[0].clone();
     let matches = match Options::new().optflag("h", "help", "").parse(&args[1..]) {
         Ok(m) => m,
         Err(f) => {
             usage(&prog, f.to_string().as_str());
-            return;
+            return Ok(());
         }
     };
     if matches.opt_present("h") || matches.free.len() != 2 {
         usage(&prog, "");
-        return;
+        return Ok(());
     }
 
     let lex_l_path = &matches.free[0];
     let lex_src = read_file(lex_l_path);
-    let lexerdef = LRNonStreamingLexerDef::<DefaultLexerTypes<u32>>::from_str(&lex_src)
-        .unwrap_or_else(|errs| {
-            let nlcache = NewlineCache::from_str(&lex_src).unwrap();
-            for e in errs {
-                if let Some((line, column)) = nlcache
-                    .byte_to_line_num_and_col_num(&lex_src, e.spans().first().unwrap().start())
-                {
-                    writeln!(
-                        stderr(),
-                        "{}: {} at line {line} column {column}",
-                        &lex_l_path,
-                        &e
-                    )
-                    .ok();
-                } else {
-                    writeln!(stderr(), "{}: {}", &lex_l_path, &e).ok();
-                }
+    let lex_diag = SpannedDiagnosticFormatter::new(&lex_src, Path::new(lex_l_path));
+    let (mut header, _) = match GrmtoolsSectionParser::new(&lex_src, false).parse() {
+        Ok(x) => x,
+        Err(es) => {
+            eprintln!(
+                "\n{ERROR}{}",
+                lex_diag.file_location_msg(" parsing the `%grmtools` section", None)
+            );
+            for e in es {
+                eprintln!(
+                    "{}",
+                    &indent("     ", &lex_diag.format_error(e).to_string())
+                );
             }
             process::exit(1);
-        });
+        }
+    };
+    header.mark_used(&"lexerkind".to_string());
+    let lexerkind = if let Some(HeaderValue(_, lk_val)) = header.get("lexerkind") {
+        LexerKind::try_from(lk_val)?
+    } else {
+        LexerKind::LRNonStreamingLexer
+    };
+
+    let lexerdef = match lexerkind {
+        LexerKind::LRNonStreamingLexer => {
+            let lex_flags = LexFlags::try_from(&mut header)?;
+            let lexerdef = match LRNonStreamingLexerDef::<DefaultLexerTypes<u32>>::new_with_options(
+                &lex_src, lex_flags,
+            ) {
+                Ok(x) => x,
+                Err(errs) => {
+                    eprintln!("\n{ERROR}{}", lex_diag.file_location_msg("", None));
+                    for e in errs {
+                        eprintln!(
+                            "{}",
+                            &indent("     ", &lex_diag.format_error(e).to_string())
+                        );
+                    }
+                    process::exit(1);
+                }
+            };
+            lexerdef
+        }
+        _ => {
+            return Err(ErrorString("Unrecognized lexer kind".to_string()))?;
+        }
+    };
+    {
+        let unused_header_values = header.unused();
+        if !unused_header_values.is_empty() {
+            return Err(ErrorString(format!(
+                "Unused header values: {}",
+                unused_header_values.join(", ")
+            )))?;
+        }
+    }
     let input = &read_file(&matches.free[1]);
     for r in lexerdef.lexer(input).iter() {
         match r {
@@ -93,4 +152,19 @@ fn main() {
             }
         }
     }
+    Ok(())
+}
+
+/// Indents a multi-line string and trims any trailing newline.
+/// This currently assumes that indentation on blank lines does not matter.
+///
+/// The algorithm used by this function is:
+/// 1. Prefix `s` with the indentation, indenting the first line.
+/// 2. Trim any trailing newlines.
+/// 3. Replace all newlines with `\n{indent}`` to indent all lines after the first.
+///
+/// It is plausible that we should a step 4, but currently do not:
+/// 4. Replace all `\n{indent}\n` with `\n\n`
+fn indent(indent: &str, s: &str) -> String {
+    format!("{indent}{}\n", s.trim_end_matches('\n')).replace('\n', &format!("\n{}", indent))
 }