add variable declaration to parser

7 files changed, 58 insertions, 2 deletions

diff --git a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/Expression.java b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/Expression.java
index 6ca58b2..18fc585 100644
--- a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/Expression.java
+++ b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/Expression.java
@@ -4,7 +4,7 @@ import no.eliashaugsbakk.kompilator.parsing.node.ASTNode;
 
 /**
  * Base class for all expression nodes.
- * An expression is a piece of code that evaluates to a value.
+ * An expression is a piece of code that evaluates to a value. (i.e., returns a value)
  * Expressions cannot stand alone as statements; they must be used within statements.
  * <p>
  * Examples:
diff --git a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/Identifier.java b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/Identifier.java
new file mode 100644
index 0000000..c1f475f
--- /dev/null
+++ b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/Identifier.java
@@ -0,0 +1,12 @@
+package no.eliashaugsbakk.kompilator.parsing.node.expression;
+
+/**
+ * Resolves to a variable's value
+ */
+public class Identifier extends Expression {
+  final String name;
+
+  public Identifier(String name) {
+    this.name = name;
+  }
+}
diff --git a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/StringLiteral.java b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/literal/StringLiteral.java
index 67ce405..82402ed 100644
--- a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/StringLiteral.java
+++ b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/expression/literal/StringLiteral.java
@@ -1,4 +1,6 @@
-package no.eliashaugsbakk.kompilator.parsing.node.expression;
+package no.eliashaugsbakk.kompilator.parsing.node.expression.literal;
+
+import no.eliashaugsbakk.kompilator.parsing.node.expression.Expression;
 
 /**
  * Represents a string literal expression (e.g., "Hello, World").
diff --git a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/Assignment.java b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/Assignment.java
new file mode 100644
index 0000000..a54a891
--- /dev/null
+++ b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/Assignment.java
@@ -0,0 +1,13 @@
+package no.eliashaugsbakk.kompilator.parsing.node.statement;
+
+import no.eliashaugsbakk.kompilator.parsing.node.expression.Expression;
+
+public class Assignment extends Statement {
+  final String identifier;
+  final Expression expression;
+
+  public Assignment(String identifier, Expression expression) {
+    this.identifier = identifier;
+    this.expression = expression;
+  }
+}
diff --git a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/ExpressionStatement.java b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/ExpressionStatement.java
index 64bc0a8..b810a04 100644
--- a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/ExpressionStatement.java
+++ b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/ExpressionStatement.java
@@ -2,6 +2,11 @@ package no.eliashaugsbakk.kompilator.parsing.node.statement;
 
 import no.eliashaugsbakk.kompilator.parsing.node.expression.Expression;
 
+/**
+ * A statement which holds an expression.
+ * print("hello"); does not have a return value; it is a statement, but it is also
+ *    function call.
+ */
 public class ExpressionStatement extends Statement {
   public Expression expression;
   public ExpressionStatement(Expression expression) {
diff --git a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/IdentifierDeclaration.java b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/IdentifierDeclaration.java
new file mode 100644
index 0000000..e7db477
--- /dev/null
+++ b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/IdentifierDeclaration.java
@@ -0,0 +1,22 @@
+package no.eliashaugsbakk.kompilator.parsing.node.statement;
+
+import no.eliashaugsbakk.kompilator.parsing.Type;
+import no.eliashaugsbakk.kompilator.parsing.node.expression.Expression;
+
+public class IdentifierDeclaration extends Statement {
+  // identifier name: [my_var]: type = 4;
+  final String identifier;
+
+  // identifier type: my_var: [type] = 4;
+  final Type type;
+
+  // identifier initialization:  my_var: type [4];
+  // may be null: my_var: type?;
+  final Expression expression; // may be null: x: int?;
+
+  public IdentifierDeclaration(String identifier, Type type, Expression expression) {
+    this.identifier = identifier;
+    this.type = type;
+    this.expression = expression;
+  }
+}
diff --git a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/Statement.java b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/Statement.java
index fc52f9a..aed21ad 100644
--- a/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/Statement.java
+++ b/src/main/java/no/eliashaugsbakk/kompilator/parsing/node/statement/Statement.java
@@ -5,9 +5,11 @@ import no.eliashaugsbakk.kompilator.parsing.node.ASTNode;
 /**
  * Base class for all statement nodes.
  * A statement is a top-level line of code that performs an action.
+ * No return value.
  * <p>
  * Examples:
  * - print("Hello");  (function call statement)
+ * x my_value = my_func("Hello"); (not a statement - it has a return value)
  * - var x: int = 5;  (variable declaration statement)
  * - if (x > 0) { }   (conditional statement)
  */