From 01ea7da5e755559073ee29b139fd1bd19a99090e Mon Sep 17 00:00:00 2001
From: CGQAQ <m.jason.liu@outlook.com>
Date: Wed, 24 Nov 2021 07:13:52 +0800
Subject: [PATCH] parser structure code with some todos

Signed-off-by: CGQAQ <m.jason.liu@outlook.com>
---
 src/lib.rs    |   2 +
 src/parser.rs | 145 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/util.rs   |  18 +++++++
 3 files changed, 165 insertions(+)
 create mode 100644 src/parser.rs
 create mode 100644 src/util.rs

diff --git a/src/lib.rs b/src/lib.rs
index 31b3a2a..2972330 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,7 @@
+pub mod parser;
 pub mod tokenizer;
 pub mod types;
+mod util;
 
 #[cfg(test)]
 mod tests {
diff --git a/src/parser.rs b/src/parser.rs
new file mode 100644
index 0000000..c64707d
--- /dev/null
+++ b/src/parser.rs
@@ -0,0 +1,145 @@
+use crate::tokenizer::{Token, TokenType, Tokenizer};
+use crate::util;
+
+pub struct Parser<'a> {
+    css: &'a str,
+
+    // options
+    lossy: bool,
+    safe: bool, // always false
+
+    tokens: Vec<Token>,
+
+    position: usize,
+}
+
+// TODO: use this instead
+#[allow(dead_code)]
+pub struct ParserOptions {
+    lossy: bool,
+    safe: Option<bool>, // always false
+}
+
+pub struct Parse {}
+
+pub struct Node {}
+
+impl<'a> Parser<'a> {
+    pub fn new(css: &'a str, lossy: bool) -> Parser {
+        Parser {
+            // input
+            css,
+
+            // options
+            lossy,
+            safe: false,
+
+            // tokens generated from input
+            tokens: Tokenizer::new(css, None).tokenize(),
+            position: 0,
+        }
+    }
+
+    pub fn parse(mut self) -> Parse {
+        while self.position < self.tokens.len() {
+            self.parse_token();
+        }
+
+        todo!("constructing Parse");
+    }
+
+    fn parse_token(&mut self /*throw on missing parenthesis*/) -> Node {
+        let current_token = &self.tokens[self.position];
+        match current_token.ty {
+            TokenType::Space => self.parse_space(),
+            TokenType::Comment => self.parse_comment(),
+            TokenType::OpenParenthesis => self.parse_parenthesis(),
+            TokenType::CloseParenthesis => {
+                // if throw on missing parenthesis; then
+                util::expected(vec!["opening parenthesis"], current_token.pos.0, None);
+            }
+            TokenType::OpenSquare => self.parse_attribute(),
+
+            ty @ _
+                if ty == TokenType::Dollar
+                    || ty == TokenType::Caret
+                    || ty == TokenType::Equals
+                    || ty == TokenType::Word =>
+            {
+                self.parse_word();
+            }
+
+            TokenType::Colon => {
+                self.parse_pseudo();
+            }
+            TokenType::Comma => {
+                self.parse_comma();
+            }
+            TokenType::Asterisk => {
+                self.parse_universal();
+            }
+            TokenType::Ampersand => {
+                self.parse_ampersand();
+            }
+
+            ty @ _ if ty == TokenType::Slash || ty == TokenType::Combinator => {
+                self.parse_combinator();
+            }
+            TokenType::SingleQuote => {
+                self.parse_string();
+            }
+            TokenType::CloseSquare => {}
+            TokenType::Semicolon => {}
+
+            // TODO(CGQAQ): Why these will panic?
+            TokenType::At => {}
+            TokenType::Tilde => {}
+            TokenType::Plus => {}
+            TokenType::Pipe => {}
+            TokenType::Greater => {}
+            TokenType::DoubleQuote => {}
+            TokenType::Bang => {}
+            TokenType::Backslash => {}
+            TokenType::Cr => {}
+            TokenType::Feed => {}
+            TokenType::Newline => {}
+            TokenType::Tab => {}
+        }
+
+        todo!("Maybe not returning a Node?")
+    }
+
+    fn parse_space() {
+        todo!("impl parse_space")
+    }
+    fn parse_comment() {
+        todo!("impl parse_comment")
+    }
+    fn parse_parenthesis() {
+        todo!("impl parse_parenthesis")
+    }
+    fn parse_attribute() {
+        todo!("impl parse_attribute")
+    }
+    fn parse_word() {
+        todo!("impl parse_word")
+    }
+    fn parse_pseudo() {
+        todo!("impl parse_pseudo")
+    }
+    fn parse_comma() {
+        todo!("impl parse_comma")
+    }
+    fn parse_universal() {
+        todo!("impl parse_universal")
+    }
+    fn parse_nesting() {
+        todo!("impl parse_nesting")
+    }
+    fn parse_combinator() {
+        todo!("impl parse_combinator")
+    }
+    fn parse_string() {
+        todo!("impl parse_string")
+    }
+}
diff --git a/src/util.rs b/src/util.rs
new file mode 100644
index 0000000..cdde5fc
--- /dev/null
+++ b/src/util.rs
@@ -0,0 +1,18 @@
+pub fn expected(mut description: Vec<&str>, index: usize, found: Option<&str>) {
+    let last = description.pop();
+    let description = format!("{} or {}", description.join(", "), last.unwrap_or(""));
+    let an = if ['a', 'e', 'i', 'o', 'u'].contains(description[0]) {
+        "an"
+    } else {
+        "a"
+    };
+
+    if let Some(founded) = found {
+        panic!(
+            "Expected {} {}, found \"{}\" instead. At #{}",
+            an, description, founded, index
+        );
+    }
+
+    panic!("Expected {} {}. At #{}", an, description, index);
+}