diff --git a/src/compiler/Compiler.h b/src/compiler/Compiler.h
new file mode 100644
index 0000000..6124102
--- /dev/null
+++ b/src/compiler/Compiler.h
@@ -0,0 +1,34 @@
+#pragma once
+#include "../std.h"
+#include "../collections/List.h"
+#include "Token.h"
+#include "AST.h"
+
+typedef enum CompilerState {
+    CompilerState_Initial,
+    CompilerState_Lexing,
+    CompilerState_Parsing,
+    CompilerState_Compiling,
+    CompilerState_Error,
+    CompilerState_Success
+} CompilerState;
+
+typedef struct Compiler {
+    char* code;
+    u32 code_len;
+    u32 column;     // > 0 if code parsing started
+    u32 pos;
+    CompilerState state;
+    NULLABLE(char* error_message);
+    List_Token tokens;
+    List_u32 line_lengths;
+    AST ast;
+    u32 tok_i;
+} Compiler;
+
+void Compiler_init(Compiler* cmp);
+void Compiler_free(Compiler* cmp);
+
+/// @brief compile assembly language code to machine code
+/// @return true if no errors, false if any error occured (check cmp->error_message)
+bool Compiler_compile(Compiler* cmp, cstr source_file_name, cstr out_file_name, bool debug);
diff --git a/src/compiler/Compiler_internal.h b/src/compiler/Compiler_internal.h
new file mode 100644
index 0000000..f3ce11c
--- /dev/null
+++ b/src/compiler/Compiler_internal.h
@@ -0,0 +1,29 @@
+#include "Compiler.h"
+
+void _Compiler_setError(Compiler* cmp, cstr context, cstr format, ...) __attribute__((__format__(__printf__, 3, 4)));
+
+#define Compiler_setError(cmp, format, ...) _Compiler_setError(cmp, __func__, format ,##__VA_ARGS__)
+
+#define returnError(FORMAT, ...) {\
+    setError(FORMAT, ##__VA_ARGS__);\
+    return false;\
+}
+
+#define returnErrorIf(STATEMENT, FORMAT, ...) if(STATEMENT) returnError(FORMAT, ##__VA_ARGS__)
+
+#define returnErrorIf_auto(STATEMENT) returnErrorIf(STATEMENT, #STATEMENT)
+
+typedef struct CodePos {
+    u32 line; // 0 on error
+    u32 column; // 0 on error
+} CodePos;
+
+#define CodePos_create(L, C) ((CodePos){ .line = L, .column = C })
+
+/// @param pos index in code buffer
+CodePos Compiler_getLineAndColumn(Compiler* cmp, u32 pos);
+
+char* Compiler_extractTokenStr(Compiler* cmp, Token t);
+
+bool Compiler_lex(Compiler* cmp);
+bool Compiler_parse(Compiler* cmp);
diff --git a/src/compiler/Parser.c b/src/compiler/Parser.c
new file mode 100644
index 0000000..ebf366b
--- /dev/null
+++ b/src/compiler/Parser.c
@@ -0,0 +1,68 @@
+#include "Compiler_internal.h"
+
+#define setError(FORMAT, ...) {\
+    cmp->pos = cmp->tokens.data[cmp->tok_i].begin;\
+    Compiler_setError(cmp, FORMAT, ##__VA_ARGS__);\
+}
+
+#define setError_unexpectedToken(T) {\
+    char* tok_str = Compiler_extractTokenStr(cmp, T);\
+    setError("unexpected character '%s'", tok_str);\
+    free(tok_str);\
+}
+
+
+static void parseDataDefinition(Compiler* cmp, char* instr_name, DataDefinition* dataDefPtr){
+
+}
+
+
+static void parseOperation(Compiler* cmp, char* instr_name, Operation* operPtr){
+
+}
+
+bool Compiler_parse(Compiler* cmp){
+    returnErrorIf_auto(cmp->state != CompilerState_Lexing);
+    cmp->state = CompilerState_Parsing;
+    Token tok;
+    Section* sec = NULL;
+    
+    while(cmp->tok_i < cmp->tokens.len){
+        tok = cmp->tokens.data[cmp->tok_i];
+        switch(tok.type){
+            case TokenType_Unset:
+                returnError("token of undefined type");
+            case TokenType_SingleLineComment:
+            case TokenType_MultiLineComment:
+                // skip comments
+                break;
+            case TokenType_Label:
+                // create new section
+                sec = List_Section_expand(&cmp->ast.sections);
+                Section_init(sec, Compiler_extractTokenStr(cmp, tok));
+                break;
+            case TokenType_Instruction:
+                char* instr_name = Compiler_extractTokenStr(cmp, tok);
+                // data definition starts with const
+                if(cstr_seek(instr_name, "const", 0, 1)){
+                    DataDefinition* dataDefPtr = List_DataDefinition_expand(&sec->data);
+                    parseDataDefinition(cmp, instr_name, dataDefPtr);
+                }
+                else {
+                    Operation* operPtr = List_Operation_expand(&sec->code);
+                    parseOperation(cmp, instr_name, operPtr);
+                }
+                break;
+            default:
+                setError_unexpectedToken(tok);
+                return false;
+        }
+
+        if(cmp->state == CompilerState_Error)
+            return false;
+
+        cmp->tok_i++;
+    }
+
+    return true;
+}
diff --git a/src/compiler/Token.c b/src/compiler/Token.c
new file mode 100644
index 0000000..cf62d87
--- /dev/null
+++ b/src/compiler/Token.c
@@ -0,0 +1,23 @@
+#include "Token.h"
+
+List_define(Token);
+
+static cstr _TokenType_str[] = {
+    "Unset",
+    "SingleLineComment",
+    "MultiLineComment",
+    "Instruction",
+    "Label",
+    "Number",
+    "Char",
+    "String",
+    "Name",
+    "NamedDataPointer",
+    "NamedDataSize"
+};
+
+cstr TokenType_toString(TokenType t){
+    if(t >= ARRAY_SIZE(_TokenType_str))
+        return "!!INDEX_ERROR!!";
+    return _TokenType_str[t];
+}
diff --git a/src/compiler/Token.h b/src/compiler/Token.h
new file mode 100644
index 0000000..2a4faad
--- /dev/null
+++ b/src/compiler/Token.h
@@ -0,0 +1,29 @@
+#pragma once
+#include "../std.h"
+#include "../collections/List.h"
+
+typedef enum TokenType {
+    TokenType_Unset,                // initial value
+    TokenType_SingleLineComment,    // //comment
+    TokenType_MultiLineComment,     // /* comment */
+    TokenType_Instruction,          // abc
+    TokenType_Label,                // .abc:
+    TokenType_Number,               // 0123
+    TokenType_Char,                 // 'A'
+    TokenType_String,               // "aaaa"
+    TokenType_Name,                 // xyz
+    TokenType_NamedDataPointer,     // @xyz
+    TokenType_NamedDataSize         // #xyz
+} TokenType;
+
+cstr TokenType_toString(TokenType t);
+
+typedef struct Token {
+    u32 begin;          // some index in Compiler->code
+    u32 length : 24;    // length in characters (24 bits)
+    TokenType type : 8; // type of token (8 bits)
+} Token;
+
+List_declare(Token);
+
+#define Token_construct(TYPE, BEGIN, END) ((Token){ .type = TYPE, .begin = BEGIN, .length = END })