From 1588c0407d7cd649cadec7e71c16c2073afa3b63 Mon Sep 17 00:00:00 2001
From: Garrit Franke <garrit@slashdev.space>
Date: Mon, 15 Feb 2021 20:38:33 +0100
Subject: [PATCH] feat: basic field access

---
 src/generator/c.rs      |  2 ++
 src/generator/js.rs     | 10 ++++++++--
 src/lexer/mod.rs        |  3 +++
 src/parser/node_type.rs |  1 +
 src/parser/rules.rs     |  9 +++++++++
 tests/structs.sb        | 17 +++++++++++++++++
 6 files changed, 40 insertions(+), 2 deletions(-)
 create mode 100644 tests/structs.sb

diff --git a/src/generator/c.rs b/src/generator/c.rs
index d921940..02da8ea 100644
--- a/src/generator/c.rs
+++ b/src/generator/c.rs
@@ -127,6 +127,7 @@ fn generate_expression(expr: Expression) -> String {
         Expression::ArrayAccess(name, expr) => generate_array_access(name, *expr),
         Expression::BinOp(left, op, right) => generate_bin_op(*left, op, *right),
         Expression::StructInitialization(_, _) => todo!(),
+        Expression::FieldAccess(_, _) => todo!(),
     }
 }
 
@@ -220,6 +221,7 @@ fn generate_function_call(func: String, args: Vec<Expression>) -> String {
             Expression::Array(_) => todo!(),
             Expression::BinOp(left, op, right) => generate_bin_op(*left, op, *right),
             Expression::StructInitialization(_, _) => todo!(),
+            Expression::FieldAccess(_, _) => todo!(),
         })
         .collect::<Vec<String>>()
         .join(",");
diff --git a/src/generator/js.rs b/src/generator/js.rs
index 5f64717..0a05cc2 100644
--- a/src/generator/js.rs
+++ b/src/generator/js.rs
@@ -119,7 +119,8 @@ fn generate_expression(expr: Expression) -> String {
         Expression::BinOp(left, op, right) => generate_bin_op(*left, op, *right),
         Expression::StructInitialization(name, fields) => {
             generate_struct_initialization(name, fields)
-        }
+        },
+        Expression::FieldAccess(expr, field) => generate_field_access(*expr, field),
     }
 }
 
@@ -230,7 +231,8 @@ fn generate_function_call(func: String, args: Vec<Expression>) -> String {
             Expression::BinOp(left, op, right) => generate_bin_op(*left, op, *right),
             Expression::StructInitialization(name, fields) => {
                 generate_struct_initialization(name, fields)
-            }
+            },
+            Expression::FieldAccess(expr, field) => generate_field_access(*expr, field),
         })
         .collect::<Vec<String>>()
         .join(",");
@@ -286,6 +288,10 @@ fn generate_struct_initialization(
     out_str
 }
 
+fn generate_field_access(expr: Expression, field: String) -> String {
+    format!("{}.{}", generate_expression(expr), field)
+}
+
 fn generate_assign(name: Expression, expr: Expression) -> String {
     format!(
         "{} = {}",
diff --git a/src/lexer/mod.rs b/src/lexer/mod.rs
index e71eef5..14586e4 100644
--- a/src/lexer/mod.rs
+++ b/src/lexer/mod.rs
@@ -72,6 +72,8 @@ pub enum TokenKind {
     Colon,
     /// ";"
     SemiColon,
+    /// "."
+    Dot,
     /// "!"
     Exclamation,
     /// ","
@@ -203,6 +205,7 @@ impl Cursor<'_> {
             c if is_whitespace(c) => self.whitespace(),
             '0'..='9' => self.number(),
             '"' | '\'' => self.string(),
+            '.' => Dot,
             '+' => match self.first() {
                 '=' => {
                     self.bump();
diff --git a/src/parser/node_type.rs b/src/parser/node_type.rs
index f9bcc67..5b2a716 100644
--- a/src/parser/node_type.rs
+++ b/src/parser/node_type.rs
@@ -114,6 +114,7 @@ pub enum Expression {
     ArrayAccess(String, Box<Expression>),
     BinOp(Box<Expression>, BinOp, Box<Expression>),
     StructInitialization(String, HashMap<String, Box<Expression>>),
+    FieldAccess(Box<Expression>, String)
 }
 
 impl TryFrom<Token> for Expression {
diff --git a/src/parser/rules.rs b/src/parser/rules.rs
index cd45bf9..024cb76 100644
--- a/src/parser/rules.rs
+++ b/src/parser/rules.rs
@@ -298,6 +298,15 @@ impl Parser {
                             Err(_) => arr,
                         }
                     }
+                    TokenKind::Dot => {
+                        let subject = Expression::Variable(token.raw);
+                        self.match_token(TokenKind::Dot)?;
+                        let field = self.match_identifier()?;
+                        match BinOp::try_from(self.peek()?.kind) {
+                            Ok(_) => self.parse_bin_op(Some(Expression::Variable(field)))?,
+                            Err(_) => return Ok(Expression::FieldAccess(Box::new(subject), field)),
+                        }
+                    }
                     _ => match BinOp::try_from(self.peek()?.kind) {
                         Ok(_) => self.parse_bin_op(Some(Expression::Variable(token.raw)))?,
                         Err(_) => Expression::Variable(val),
diff --git a/tests/structs.sb b/tests/structs.sb
new file mode 100644
index 0000000..ae4469a
--- /dev/null
+++ b/tests/structs.sb
@@ -0,0 +1,17 @@
+struct User {
+    username: string,
+    first_name: string,
+    last_name: string
+}
+
+fn test_initialization() {
+    let foo = new User {
+        username: "Foo Bar",
+        first_name: "Bar",
+        last_name: "Foo Bar"
+    }
+}
+
+fn main() {
+    test_initialization()
+}
\ No newline at end of file