ll checker

src/double_enum.rs

@@ -30,5 +30,12 @@ macro_rules! double_enum {
                 other.eq(self)
             }
         }
+        impl From<$name> for $bare_name{
+            fn from(value: $name) -> Self {
+                match value  {
+                    $($name::$variant{ .. } => $bare_name::$variant,)*
+                }
+            }
+        }
     }
 }

src/ll_grammar.rs

@@ -7,6 +7,7 @@ use std::{
 #[macro_export]
 macro_rules! ll_grammar {
     (
+        start: $start:ident;
         $(
             $left:ident -> $(
                 $right:ident
@@ -22,9 +23,11 @@ macro_rules! ll_grammar {
                 map.get_mut(&$left).unwrap().push(vec![$($right.into()),*]);
             })*
             $crate::ll_grammar::LLGrammar {
+                start: $start,
                 rules: map,
                 first: None,
                 follow: None,
+                parse_table: None,
             }
         }
     };
@@ -37,16 +40,19 @@ pub enum Sentential<T, N> {
 }
 
 pub struct LLGrammar<N: PartialEq + Eq + Hash + Clone, T: PartialEq + Eq + Hash + Clone> {
+    pub start: N,
     pub rules: HashMap<N, Vec<Vec<Sentential<T, N>>>>,
     /// none is epsilon
     pub first: Option<HashMap<N, HashSet<Option<T>>>>,
     /// none is $
     pub follow: Option<HashMap<N, HashSet<Option<T>>>>,
+
+    // When in State N and reading T, then apply the usize'th rule of N.
+    /// none is $
+    pub parse_table: Option<HashMap<(N, Option<T>), usize>>,
 }
 
-impl<N: PartialEq + Eq + Hash + Clone + Debug, T: PartialEq + Eq + Hash + Clone + Debug>
+impl<N: PartialEq + Eq + Hash + Clone, T: PartialEq + Eq + Hash + Clone> LLGrammar<N, T> {
-    LLGrammar<N, T>
-{
     pub fn can_produce_epsilon(&self, rule: &Sentential<T, N>) -> bool {
         match rule {
             Sentential::Terminal(_) => false,
@@ -147,12 +153,12 @@ impl<N: PartialEq + Eq + Hash + Clone + Debug, T: PartialEq + Eq + Hash + Clone
         out
     }
 
-    pub fn gen_follow(&mut self, start: N) {
+    pub fn gen_follow(&mut self) {
         if self.first == None {
             self.gen_first();
         }
         let mut follow: HashMap<N, HashSet<Option<T>>> = HashMap::new();
-        follow.insert(start, HashSet::from([None]));
+        follow.insert(self.start.clone(), HashSet::from([None]));
         loop {
             let mut change = false;
 
@@ -228,4 +234,149 @@ impl<N: PartialEq + Eq + Hash + Clone + Debug, T: PartialEq + Eq + Hash + Clone
         }
         self.follow = Some(follow);
     }
+
+    pub fn follow(&self, none_termianl: &N) -> HashSet<Option<T>> {
+        assert!(self.follow.is_some(), "Please call gen_follow before this!");
+        self.follow
+            .as_ref()
+            .unwrap()
+            .get(&none_termianl)
+            .cloned()
+            .unwrap_or(HashSet::new())
+    }
+
+    pub fn gen_parse_table(&mut self) -> bool {
+        if self.follow.is_none() {
+            self.gen_follow();
+        }
+        if self.parse_table.is_some() {
+            return false;
+        }
+        let mut conflict = false;
+        let mut parse_table: HashMap<(N, Option<T>), usize> = HashMap::new();
+        for (from, to) in self.rules.iter() {
+            for (id, to) in to.iter().enumerate() {
+                // rule is A -> al
+                // terminal == None means epsilon
+                for terminal in self.first(to) {
+                    match terminal {
+                        // let a be in First(al) -> add to T[A,a] = A->al (using the index of al)
+                        Some(terminal) => {
+                            conflict |= parse_table
+                                .insert((from.clone(), Some(terminal.clone())), id)
+                                .is_some();
+                        }
+                        // if first contains epsilon then
+                        // let b be in Follow(A) -> add to T[A,b] = A->al (using the index of al)
+                        None => {
+                            for terminal in self.follow(from).iter() {
+                                conflict |= parse_table
+                                    .insert((from.clone(), terminal.clone()), id)
+                                    .is_some()
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        self.parse_table = Some(parse_table);
+        conflict
+    }
+
+    /// get parse_table rule
+    /// None means error.
+    pub fn parse_table(
+        &self,
+        none_terminal: &N,
+        terminal: &Option<T>,
+    ) -> Option<&Vec<Sentential<T, N>>> {
+        assert!(
+            self.parse_table.is_some(),
+            "Please call gen_parse_table before this!"
+        );
+        self.parse_table
+            .as_ref()
+            .unwrap()
+            .get(&(none_terminal.clone(), terminal.clone()))
+            .and_then(|f| self.rules.get(none_terminal).and_then(|rule| rule.get(*f)))
+    }
+
+    pub fn create_checker<'a, S: Into<T> + PartialEq<T> + Clone>(
+        &'a self,
+        iter: &'a mut dyn Iterator<Item = S>,
+    ) -> LLTabelParser<N, T, S> {
+        assert!(
+            self.parse_table.is_some(),
+            "Please call gen_parse_table before this!"
+        );
+        LLTabelParser {
+            input: iter,
+            grammar: self,
+        }
+    }
+}
+
+/// Just checks a program. Does not generates output.
+pub struct LLTabelParser<
+    'a,
+    N: PartialEq + Eq + Hash + Clone,
+    T: PartialEq + Eq + Hash + Clone,
+    S: Into<T> + PartialEq<T> + Clone,
+> {
+    grammar: &'a LLGrammar<N, T>,
+    input: &'a mut dyn Iterator<Item = S>,
+}
+
+impl<
+        'a,
+        N: PartialEq + Eq + Hash + Clone + Debug,
+        T: PartialEq + Eq + Hash + Clone + Debug,
+        S: Into<T> + PartialEq<T> + Clone + Debug,
+    > LLTabelParser<'a, N, T, S>
+{
+    pub fn parse(&mut self) -> bool {
+        let mut stack: Vec<Sentential<Option<T>, N>> = vec![
+            Sentential::Terminal(None),
+            Sentential::NoneTerminal(self.grammar.start.clone()),
+        ];
+        let mut next = self.input.next();
+        loop {
+            if next.is_none() {
+                println!("EOF");
+                return self.input.size_hint().0 == 0;
+            }
+            let state = stack.pop();
+            match state {
+                Some(Sentential::Terminal(t)) => match (next, t) {
+                    (Some(a), Some(b)) if a == b => {
+                        next = self.input.next();
+                    }
+                    (None, None) => {
+                        next = self.input.next();
+                    }
+                    (a, b) => {
+                        println!("not matching terminals: {a:?}, {b:?}");
+                        return false;
+                    }
+                },
+                Some(Sentential::NoneTerminal(nt)) => {
+                    let Some(a) = self
+                        .grammar
+                        .parse_table(&nt, &next.as_ref().map(|f| f.clone().into()))
+                    else {
+                        println!("no parse table entry: {nt:?} next: {next:?}");
+                        return false;
+                    };
+                    stack.extend(a.iter().rev().map(|f| match f {
+                        Sentential::Terminal(t) => Sentential::Terminal(Some(t.clone())),
+                        Sentential::NoneTerminal(nt) => Sentential::NoneTerminal(nt.clone()),
+                    }));
+                }
+                None => {
+                    println!("EOS");
+                    return false;
+                }
+            }
+        }
+    }
 }

src/main.rs

@@ -9,13 +9,23 @@ use std::collections::HashMap;
 double_enum!(
     BareTokens, Tokens {
         WhiteSpace,
+        Semicolon,
         Add,
         Sub,
         Mul,
         Div,
+        Eq,
+        Neq,
+        Assign,
         While,
+        If,
         LBrace,
         RBrace,
+        LSBrace,
+        RSBrace,
+        LQBrace,
+        RQBrace,
+        Dot,
         Ident(String),
         Int(i64),
         Float(f64),
@@ -27,6 +37,9 @@ scanner!(
     r"^\s|\t|\n" : |_,_| {
         Some(WhiteSpace)
     }
+    r"^;" : |_,_| {
+        Some(Semicolon)
+    }
     r"^\+" : |_,_| {
         Some(Add)
     }
@@ -39,18 +52,42 @@ scanner!(
     r"^/" : |_,_| {
         Some(Div)
     }
+    r"^==" : |_,_| {
+        Some(Eq)
+    }
+    r"^!=" : |_,_| {
+        Some(Neq)
+    }
+    r"^=" : |_,_| {
+        Some(Assign)
+    }
     r"^while" : |_,_| {
         Some(While)
     }
-    r"\(" : |_,_| {
+    r"^\(" : |_,_| {
         Some(LBrace)
     }
-    r"\)" : |_,_| {
+    r"^\)" : |_,_| {
         Some(RBrace)
     }
+    r"^\[" : |_,_| {
+        Some(LSBrace)
+    }
+    r"^\]" : |_,_| {
+        Some(RSBrace)
+    }
+    r"^\{" : |_,_| {
+        Some(LQBrace)
+    }
+    r"^\}" : |_,_| {
+        Some(RQBrace)
+    }
     r"^[a-zA-Z](\w)*" : |_, m: Match<'_>| {
         Some(Ident(String::from(m.as_str())))
     }
+    r"^\." : |_, _| {
+        Some(Dot)
+    }
     r"^[0-9]+.[0-9]*" : |_, m: Match<'_>| {
         m.as_str().parse::<_>().ok().map(|f| Float(f))
     }
@@ -61,12 +98,13 @@ scanner!(
 
 #[derive(Debug, PartialEq, Eq, Hash, Clone)]
 enum NoneTerminals {
-    P,
+    P,  // Program, ; separated
-    E,
+    E,  // Expression one line
-    Ei,
+    Ei, // Expression extended additive
-    T,
+    T,  // Term, only containing Factors
-    Ti,
+    Ti, // Term extend multiplicative
-    F,
+    F,  // Factor
+    FI, // Factor extended with complex types and operators
 }
 
 impl<T> From<NoneTerminals> for Sentential<T, NoneTerminals> {
@@ -85,8 +123,14 @@ fn grammer() -> LLGrammar<NoneTerminals, BareTokens> {
     use BareTokens::*;
     use NoneTerminals::*;
     ll_grammar![
-        P -> E;
+        start: P;
+        P -> E,Semicolon,P;
+        P -> ;
         E -> T,Ei;
+        E -> While,LBrace,E,RBrace,LQBrace,P,RQBrace;
+        Ei -> Assign,T,Ei;
+        Ei -> Eq,T,Ei;
+        Ei -> Neq,T,Ei;
         Ei -> Add,T,Ei;
         Ei -> Sub,T,Ei;
         Ei -> ;
@@ -97,21 +141,30 @@ fn grammer() -> LLGrammar<NoneTerminals, BareTokens> {
         F -> LBrace, E, RBrace;
         F -> Int;
         F -> Float;
-        F -> Ident;
+        F -> Ident,FI;
+        FI -> ;
+        FI -> LBrace,E,RBrace;
+        FI -> Dot, FI;
+        FI -> LSBrace,E,RSBrace;
     ]
 }
+
 fn main() {
-    let code = String::from("while 12 + a - 3.4 / 0. * 4");
+    let code = String::from("a = 4; while(a != 5) {a = a+1;};");
     let mut m = Scanner::<Tokens>::new(code).with_skipping(Tokens::WhiteSpace);
-    for token in m.iter_mut() {
+    /* for token in m.iter_mut() {
         println!("{:?}", token);
-    }
+    } */
-    if !m.is_empty() {
-        println!("Error");
-    }
 
     let mut grammar = grammer();
-    grammar.gen_follow(NoneTerminals::P);
+    grammar.gen_follow();
     println!("first: {:?}", grammar.first);
     println!("follow: {:?}", grammar.follow);
+    let conflict = grammar.gen_parse_table();
+    println!("conflict: {conflict}");
+    println!("prase table: {:?}", grammar.parse_table);
+    println!(
+        "parsed: {}",
+        grammar.create_checker(&mut m.iter_mut()).parse()
+    )
 }

src/scanner.rs

@@ -1,4 +1,4 @@
-use std::marker::PhantomData;
+use std::{iter::Peekable, marker::PhantomData};
 
 #[macro_export]
 macro_rules! scanner {
@@ -73,4 +73,10 @@ impl<'a, T: MatchNext<T> + PartialEq> Iterator for ScannerIter<'a, T> {
             return None;
         }
     }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (
+            if self.0.code.is_empty() { 0 } else { 1 },
+            Some(self.0.code.len()),
+        )
+    }
 }