Sync

src/lang.rs

@@ -1,3 +1,5 @@
+use std::str::Chars;
+
 struct Type {
     name: String,
     params: Vec<Type>,
@@ -29,7 +31,6 @@ struct Class {
     entries: Vec<Decl>,
     methods: Vec<Function>,
 }
-struct Block(Vec<Statement>);
 struct Function {
     annotations: Vec<Annotation>,
     name: String,
@@ -50,6 +51,7 @@ enum Annotation {
     Expr(String),
 }
 enum Statement {
+    Class(Class),
     DeclLet(Decl),
     DeclVar(Decl),
     Assignment {
@@ -74,30 +76,94 @@ enum Expr {
     String(String),
     Number(String),
 }
-
-enum TopLevel {
-    Class(Class),
-    Statement(Statement)
-}
-struct Program(Vec<TopLevel>);
+struct Block(Vec<Statement>);
 struct ParseError(String);
-struct Reader(String);
-impl Reader {
-
+enum Part {
+    Set(&'static str),
+    Raw(&'static str),
 }
-trait Parsed {
-    fn enter(reader: &mut Reader) -> ;
-    fn exit(reader: &mut Reader) -> Result<(), ParseError>;
+enum Selector {
+    Cap(Pattern),
+    One(Part),
+    Any(Part),
 }
-impl Parsed for TopLevel {
-
+struct Pattern(&'static [Selector]);
+impl Pattern {
+    fn eval<'a>(&self, str: &'a str) -> Result<(&'a str, Vec<&'a str>), ()> {
+        let mut captures = Vec::new();
+        let mut current = str;
+        let mut count = 0;
+        self.0.iter().try_for_each(|selector: &Selector| {
+            match selector {
+                Selector::Cap(pattern) => {
+                    pattern.eval(str).and_then(|(sum, _)| {
+                        captures.push(sum);
+                        Ok(())
+                    })
+                },
+                Selector::Any(part) => {
+                    let mut delta = 0;
+                    match part {
+                        Part::Set(set) => {
+                            delta = current.chars().take_while(|char| set.contains(*char)).count();
+                            current = &current[delta..];
+                        },
+                        Part::Raw(raw) => {
+                            while current.starts_with(raw) {
+                                delta += raw.len();
+                                current = &current[delta..];
+                            }
+                        },
+                    }
+                    count += delta;
+                    Ok(())
+                }
+                Selector::One(part) => {
+                    match part {
+                        Part::Set(set) => {
+                            let res = current.chars().next().is_some_and(|char| set.contains(char));
+                            if res {
+                                current = &current[1..];
+                                count += 1;
+                            }
+                            res
+                        },
+                        Part::Raw(raw) => {
+                            let res = current.starts_with(raw);
+                            if res {
+                                current = &current[raw.len()..];
+                                count += raw.len();
+                            }
+                            res
+                        }
+                    }.then_some(()).ok_or(())
+                }
+            }
+        }).map(|_| (&str[..count],captures))
+    }
 }
-impl Parsed for Statement {
-
+const IDENTIFIER_START_SET: &str = "abcdefghijklmnopqrstuvwxyz_";
+const IDENTIFIER_REST_SET: &str = "abcdefghijklmnopqrstuvwxyz_1234567890";
+const WHITESPACE_SET: &str = "\n\r\t ";
+const PATTERN_IDENTIFIER: Pattern = Pattern(&[
+    Selector::One(Part::Set(IDENTIFIER_START_SET)),
+    Selector::Any(Part::Set(IDENTIFIER_REST_SET)),
+]);
+const PATTERN_WHITESPACE: Pattern = Pattern(&[Selector::Any(Part::Set(WHITESPACE_SET))]);
+const PATTERN_COMMENT: Pattern = Pattern(&[Selector::Any(Part::Raw())]);
+const PATTERN_CALL_START: Pattern = Pattern(&[
+    Selector::Cap(PATTERN_IDENTIFIER),
+    Selector::One(Part::Set("("))
+]);
+fn parse_call(str: &str) -> Result<Block,ParseError> {
+    PATTERN_CALL_START.eval(str).and_then(|_| {
+        Ok(())
+    });
+    Ok(Block(vec!()))
 }
-impl Parsed for Expr {
-
+fn parse_block(str: &str) -> Result<Block,ParseError> {
+    parse_call(str)
 }
-fn parse(source: String) -> Result<Program,ParseError> {
-    Ok(Program(Vec::new()))
+fn parse(source: &str) -> Result<Block,ParseError> {
+    parse_block(source)
 }