Allow precedence expressions to omit operator classes

crates/codegen/ebnf/src/ebnf_writer.rs

@@ -0,0 +1,73 @@
+#[derive(Debug)]
+#[allow(non_camel_case_types)]
+pub enum TokenKind {
+    comment,
+    constant,
+    keyword,
+    operator,
+    string,
+}
+
+pub trait EBNFWriter {
+    fn write_token(&mut self, kind: TokenKind, value: &str);
+    fn write_line_break(&mut self);
+
+    fn write_production_definition(&mut self, production_name: &str);
+    fn write_production_reference(&mut self, production_name: &str);
+
+    fn write_prelude(&mut self) {}
+    fn write_postlude(&mut self) {}
+    fn write_line_start(&mut self) {}
+
+    fn write_comment(&mut self, value: &str) {
+        self.write_token(TokenKind::comment, value)
+    }
+    fn write_constant(&mut self, value: &str) {
+        self.write_token(TokenKind::constant, value)
+    }
+    fn write_keyword(&mut self, value: &str) {
+        self.write_token(TokenKind::keyword, value)
+    }
+    fn write_operator(&mut self, value: &str) {
+        self.write_token(TokenKind::operator, value)
+    }
+    fn write_string(&mut self, value: &str) {
+        self.write_token(TokenKind::string, &Self::format_string_literal(value))
+    }
+
+    fn format_string_literal(value: &str) -> String {
+        let delimiter = if value.len() == 1 {
+            if value.contains("'") && !value.contains('"') {
+                '"'
+            } else {
+                '\''
+            }
+        } else {
+            if value.contains('"') && !value.contains("'") {
+                '\''
+            } else {
+                '"'
+            }
+        };
+
+        let formatted: String = value
+            .chars()
+            .map(|c| {
+                if c == '\'' || c == '\\' {
+                    format!("\\{}", c)
+                } else if c.is_ascii_graphic() || c == '¬' || c == '…' || c == '«' || c == '»'
+                {
+                    c.to_string()
+                } else {
+                    c.escape_unicode().to_string()
+                }
+            })
+            .collect();
+
+        return format!("{}{}{}", delimiter, formatted, delimiter);
+    }
+}
+
+pub trait EBNFWritable<W: EBNFWriter> {
+    fn write_ebnf(&self, name: &str, writer: &mut W);
+}

crates/codegen/ebnf/src/lib.rs

@@ -1,6 +1,6 @@
-mod expression;
-mod grammar;
+mod parser;
+mod precedence_parser;
 mod production;
+mod scanner;
 
-pub use grammar::GrammarEBNFGeneratorExtensions;
-pub use production::ProductionEBNFGeneratorExtensions;
+pub mod ebnf_writer;