collapse some tokens into each other in the lexer and create a very basic, incomplete validator with unit tests

Cargo.lock

@@ -4,4 +4,4 @@ version = 3
 
 [[package]]
 name = "frostwalker"
-version = "0.0.2"
+version = "0.0.3"

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "frostwalker"
-version = "0.0.2"
+version = "0.0.3"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

README.md

@@ -1,5 +1,7 @@
 # Frostwalker
-A TOML-like configuration language parser for Rust. At present, the crate has a lexer with unit tests written for common cases. A validator and parser are planned to be added.
+*Frostwalker is not stable nor ready for dependency development yet. Unless you plan to implement your own formatter, please wait for 0.1.0 to release. 0.0 versions are placeholders and will not be tagged.*
+
+A TOML-like configuration language parser for Rust. At present, the crate has a lexer and an incomplete validator with unit tests written for common cases. A formatter will eventually be added.
 
 ## Justification
 The Rust crate `toml` pulls in 8 other crates to do its job, including `serde`. While this may not be irksome to basically most Rust developers, I'm used to using severely underpowered Intel hardware so low compile times is a big focus for me so a crate made by me that requires only the standard library compared to one that requires other dependencies is preferrable.

src/lexer.rs

@@ -11,11 +11,9 @@ pub enum Class {
 	IDENTIFIER,
 	SEPARATOR,
 	EQUALS,
-	STRING,
+	LITERAL,
-	INTEGER,
 	NEWLINE,
-	TRUE,
+	BOOLEAN,
-	FALSE,
 	UNKNOWN,
 }
 
@@ -66,21 +64,21 @@ pub fn tokenize(source: &str) -> Vec<Token> {
 			}
 
 			if words[i] == "true" || words[i] == "TRUE" {
-				tree.push(Token { class: Class::TRUE, value: None });
+				tree.push(Token { class: Class::BOOLEAN, value: Some("true".to_string()) });
 				added = true;
 				i = i + 1;
 				continue;
 			}
 
 			if words[i] == "false" || words[i] == "FALSE" {
-				tree.push(Token { class: Class::FALSE, value: None });
+				tree.push(Token { class: Class::BOOLEAN, value: Some("false".to_string()) });
 				added = true;
 				i = i + 1;
 				continue;
 			}
 
 			if words[i].parse::<i32>().is_ok() {
-				tree.push(Token { class: Class::INTEGER, value: Some(words[i].to_string()) });
+				tree.push(Token { class: Class::LITERAL, value: Some(words[i].to_string()) });
 				added = true;
 				i = i + 1;
 				continue;
@@ -112,7 +110,7 @@ pub fn tokenize(source: &str) -> Vec<Token> {
 				if words[i].ends_with("\"") {
 					words[i] = words[i].chars().next().map(|c| &words[i][c.len_utf8()..]).unwrap_or("");
 					words[i] = words[i].chars().next_back().map(|_| &words[i][..words[i].len()-1]).unwrap_or("");
-					tree.push(Token { class: Class::STRING, value: Some(words[i].replace("\\\"", "\"").to_string()) });
+					tree.push(Token { class: Class::LITERAL, value: Some(words[i].replace("\\\"", "\"").to_string()) });
 					added = true;
 					i = i + 1;
 					continue;
@@ -129,7 +127,7 @@ pub fn tokenize(source: &str) -> Vec<Token> {
 						}
 						built_string = format!("{} {}", built_string, words[i].replace("\\\"", "\""));
 					}
-					tree.push(Token { class: Class::STRING, value: Some(built_string) });
+					tree.push(Token { class: Class::LITERAL, value: Some(built_string) });
 					added = true;
 					i = i + 1;
 					continue;

src/lexer_tests.rs

@@ -6,7 +6,7 @@ fn single_key() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("value".to_string()) };
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);
 }
@@ -18,9 +18,9 @@ fn single_key_array() {
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
 	let t1 = Token { class: Class::SEPARATOR, value: Some("[".to_string()) };
-	let strn = Token { class: Class::STRING, value: Some("\"value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("\"value".to_string()) };
 	let t2 = Token { class: Class::SEPARATOR, value: Some(",".to_string()) };
-	let strn2 = Token { class: Class::INTEGER, value: Some("6".to_string()) };
+	let strn2 = Token { class: Class::LITERAL, value: Some("6".to_string()) };
 	let t3 = Token { class: Class::SEPARATOR, value: Some("]".to_string()) };
 	let manual_tree = vec![id, op, t1, strn, t2, strn2, t3];
 	assert_eq!(tree, manual_tree);
@@ -43,7 +43,7 @@ fn single_key_escaped_double_quote_in_string() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("\"value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("\"value".to_string()) };
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);
 }
@@ -54,11 +54,11 @@ fn integers() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::INTEGER, value: Some("123567".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("123567".to_string()) };
 	let nl = Token { class: Class::NEWLINE, value: None };
 	let id2 = Token { class: Class::IDENTIFIER, value: Some("key2".to_string()) };
 	let op2 = Token { class: Class::EQUALS, value: None };
-	let strn2 = Token { class: Class::INTEGER, value: Some("-400".to_string()) };
+	let strn2 = Token { class: Class::LITERAL, value: Some("-400".to_string()) };
 	let manual_tree = vec![id, op, strn, nl, id2, op2, strn2];
 	assert_eq!(tree, manual_tree);
 }
@@ -69,11 +69,11 @@ fn booleans() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::TRUE, value: None };
+	let strn = Token { class: Class::BOOLEAN, value: Some("true".to_string()) };
 	let nl = Token { class: Class::NEWLINE, value: None };
 	let id2 = Token { class: Class::IDENTIFIER, value: Some("key2".to_string()) };
 	let op2 = Token { class: Class::EQUALS, value: None };
-	let strn2 = Token { class: Class::FALSE, value: None };
+	let strn2 = Token { class: Class::BOOLEAN, value: Some("false".to_string()) };
 	let manual_tree = vec![id, op, strn, nl, id2, op2, strn2];
 	assert_eq!(tree, manual_tree);
 }
@@ -84,7 +84,7 @@ fn single_key_space_in_string() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("a b c".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("a b c".to_string()) };
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);
 }
@@ -95,7 +95,7 @@ fn single_key_double_space_in_string() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("a b c  d".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("a b c  d".to_string()) };
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);
 }
@@ -108,13 +108,13 @@ fn triple_key() {
 	let nl2 = Token { class: Class::NEWLINE, value: None };
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("value".to_string()) };
 	let id2 = Token { class: Class::IDENTIFIER, value: Some("key2".to_string()) };
 	let op2 = Token { class: Class::EQUALS, value: None };
-	let strn2 = Token { class: Class::STRING, value: Some("value2".to_string()) };
+	let strn2 = Token { class: Class::LITERAL, value: Some("value2".to_string()) };
 	let id3 = Token { class: Class::IDENTIFIER, value: Some("key3".to_string()) };
 	let op3 = Token { class: Class::EQUALS, value: None };
-	let strn3 = Token { class: Class::STRING, value: Some("value3".to_string()) };
+	let strn3 = Token { class: Class::LITERAL, value: Some("value3".to_string()) };
 
 	let manual_tree = vec![id, op, strn, nl, id2, op2, strn2, nl2, id3, op3, strn3];
 	assert_eq!(tree, manual_tree);
@@ -126,7 +126,7 @@ fn comment() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("value".to_string()) };
 
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);
@@ -138,7 +138,7 @@ fn inline_comment() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("value".to_string()) };
 
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);
@@ -150,7 +150,7 @@ fn inline_comment_no_spaces() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("value".to_string()) };
 
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);
@@ -162,7 +162,7 @@ fn quoted_identifier() {
 
 	let id = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
 	let op = Token { class: Class::EQUALS, value: None };
-	let strn = Token { class: Class::STRING, value: Some("value".to_string()) };
+	let strn = Token { class: Class::LITERAL, value: Some("value".to_string()) };
 
 	let manual_tree = vec![id, op, strn];
 	assert_eq!(tree, manual_tree);

src/lib.rs

@@ -1,4 +1,8 @@
 pub mod lexer;
+pub mod validator;
 
 #[cfg(test)]
 mod lexer_tests;
+
+#[cfg(test)]
+mod validator_tests;

src/validator.rs

@@ -0,0 +1,55 @@
+use super::lexer::{Token, Class};
+
+#[derive(Debug)]
+#[derive(PartialEq)]
+enum ExpectedClass {
+	IDENTIFIER,
+	EQUALS,
+	NEWLINE,
+	LITERALORSEPARATOR,
+}
+
+pub fn validate(tree: &Vec<Token>) -> Option<String> {
+	let mut expected_token: ExpectedClass = ExpectedClass::IDENTIFIER;
+	let mut i = 0;
+	let mut line = 1;
+	while i < tree.len() {
+		if tree[i].class == Class::NEWLINE && i == 0 {
+			i = i + 1;
+			line = line + 1;
+			continue;
+		}
+
+		if tree[i].class == Class::NEWLINE && expected_token == ExpectedClass::NEWLINE {
+			i = i + 1;
+			line = line + 1;
+			expected_token = ExpectedClass::IDENTIFIER;
+			continue;
+		}
+
+		if tree[i].class == Class::UNKNOWN {
+			return Some(format!("Invalid token {} at line {}.", tree[i].value.clone().unwrap_or("None".to_string()), line));
+		}
+
+		if tree[i].class == Class::IDENTIFIER && expected_token == ExpectedClass::IDENTIFIER {
+			i = i + 1;
+			expected_token = ExpectedClass::EQUALS;
+			continue;
+		}
+
+		if tree[i].class == Class::EQUALS && expected_token == ExpectedClass::EQUALS {
+			i = i + 1;
+			expected_token = ExpectedClass::LITERALORSEPARATOR;
+			continue;
+		}
+
+		if (tree[i].class == Class::LITERAL || tree[i].class == Class::BOOLEAN) && expected_token == ExpectedClass::LITERALORSEPARATOR {
+			i = i + 1;
+			expected_token = ExpectedClass::NEWLINE;
+			continue;
+		}
+
+		return Some(format!("{:?} found where {:?} expected at line {}.", tree[i].class, expected_token, line));
+	}
+	return None;
+}

src/validator_tests.rs

@@ -0,0 +1,39 @@
+use super::validator;
+use super::lexer::{Token, Class};
+
+#[test]
+fn single_key() {
+	let t1 = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
+	let t2 = Token { class: Class::EQUALS, value: None };
+	let t3 = Token { class: Class::LITERAL, value: Some("10".to_string()) };
+	let result = validator::validate(&vec![t1, t2, t3]);
+
+	assert_eq!(result.is_none(), true);
+}
+
+#[test]
+fn triple_key() {
+	let t1 = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
+	let t2 = Token { class: Class::EQUALS, value: None };
+	let t3 = Token { class: Class::LITERAL, value: Some("10".to_string()) };
+	let nl = Token { class: Class::NEWLINE, value: None };
+	let t4 = Token { class: Class::IDENTIFIER, value: Some("key2".to_string()) };
+	let t5 = Token { class: Class::EQUALS, value: None };
+	let t6 = Token { class: Class::LITERAL, value: Some("13".to_string()) };
+	let result = validator::validate(&vec![t1, t2, t3, nl, t4, t5, t6]);
+
+	assert_eq!(result.is_none(), true);
+}
+
+#[test]
+fn triple_key_no_newline() {
+	let t1 = Token { class: Class::IDENTIFIER, value: Some("key".to_string()) };
+	let t2 = Token { class: Class::EQUALS, value: None };
+	let t3 = Token { class: Class::LITERAL, value: Some("10".to_string()) };
+	let t4 = Token { class: Class::IDENTIFIER, value: Some("key2".to_string()) };
+	let t5 = Token { class: Class::EQUALS, value: None };
+	let t6 = Token { class: Class::LITERAL, value: Some("13".to_string()) };
+	let result = validator::validate(&vec![t1, t2, t3, t4, t5, t6]);
+
+	assert_eq!(result.unwrap_or("".to_string()), "IDENTIFIER found where NEWLINE expected at line 1.".to_string());
+}