begin parser

src/parser.rs

@@ -0,0 +1,91 @@
+use crate::lexer::{Token, TokenType};
+
+pub enum ASTPart {
+    Number(AstNumber),
+    Assigment(AstAssigment),
+    Operation(AstOperation),
+    VarRead(AstVarRead),
+    NOOP
+}
+pub struct AstNumber {
+    pub value: i64,
+    pub pos: usize
+}
+pub struct AstAssigment {
+    pub variable: String,
+    pub value: Box<ASTPart>,
+    pub pos: usize
+}
+pub struct AstOperation {
+    pub operator: String,
+    pub left: Box<ASTPart>,
+    pub right: Box<ASTPart>,
+    pub pos: usize
+}
+pub struct AstVarRead {
+    pub variable: String,
+    pub pos: usize
+}
+
+
+fn is_end(input: &Token, end: &Vec<Token>) -> bool {
+    for token in end {
+        if input.typ == token.typ && (token.value == "" || input.value == token.value) {
+            return true;
+        }
+    }
+    return false;
+}
+fn next_operation(pos: &mut usize, input: &Vec<Token>, prev: ASTPart, op_ends: &Vec<Token>, parse_ends: &Vec<Token>) -> ASTPart {
+    let token = &input[*pos];
+    if is_end(token, &parse_ends) {
+        return prev;
+    }
+    *pos += 1;
+    if is_end(token, &op_ends) {
+        return prev;
+    }
+    if token.typ == TokenType::KEYWORD && token.value == "gethelj" {
+        let variable = &input[*pos];
+        *pos += 1;
+        if variable.typ != TokenType::IDENTIFIER {
+            panic!("Unexpected {:?} at {}", variable.typ, variable.pos)
+        }
+        let eq = &input[*pos];
+        if eq.typ == TokenType::SEPARATOR && eq.value == "=" {
+            *pos += 1;
+        }
+        let value = next_operation(pos, input, ASTPart::NOOP, op_ends, parse_ends);
+        return ASTPart::Assigment(AstAssigment { variable: variable.value.clone(), value: Box::new(value), pos: token.pos });
+    } else if token.typ == TokenType::NUMBER {
+        return next_operation(pos, input, ASTPart::Number(AstNumber { value: token.value.parse().unwrap(), pos: token.pos }), op_ends, parse_ends);
+    } else if token.typ == TokenType::IDENTIFIER {
+        return next_operation(pos, input, ASTPart::VarRead(AstVarRead { variable: token.value.clone(), pos: token.pos }), op_ends, parse_ends);
+    } else {
+        panic!("Unexpected {:?} at {}", token.typ, token.pos);
+    }
+}
+fn parse_internal(input: Vec<Token>, op_ends: Vec<Token>, parse_ends: Vec<Token>) -> Vec<ASTPart> {
+    let mut out: Vec<ASTPart> = vec![];
+    let mut pos = 0;
+    while pos < input.len() {
+        let op = next_operation(&mut pos, &input, ASTPart::NOOP, &op_ends, &parse_ends);
+        out.push(op);
+        if is_end(&input[pos], &parse_ends) {
+            break;
+        }
+    }
+    return out;
+}
+pub fn parse(input: Vec<Token>) -> Vec<ASTPart> {
+    let op_ends: Vec<Token> = vec![
+        Token { typ: TokenType::OPEND, value: String::from("\n"), pos: 0 },
+        Token { typ: TokenType::OPEND, value: String::from(";"), pos: 0 },
+        Token { typ: TokenType::OPEND, value: String::from("EOF"), pos: 0 }
+    ];
+    let parse_ends: Vec<Token> = vec![
+        Token { typ: TokenType::OPEND, value: String::from("EOF"), pos: 0 }
+    ];
+    let out = parse_internal(input, op_ends, parse_ends);
+    return out;
+}