diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9ce4fa034..f3821d1dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,36 +7,72 @@ set(CMAKE_CXX_STANDARD 17)
 
 add_subdirectory(deps/zen EXCLUDE_FROM_ALL)
 
-add_executable(
-  bolt
+set(ICU_DIR "${CMAKE_CURRENT_SOURCE_DIR}/build/icu/install")
+set(ICU_INCLUDE_DIRS "${ICU_DIR}/include")
+set(ICU_LIBRARY_DIRS "${ICU_DIR}/lib")
+
+add_library(
+  BoltCore
+  src/Text.cc
   src/CST.cc
   src/Diagnostics.cc
   src/Scanner.cc
   src/Parser.cc
   src/Checker.cc
-  src/main.cc
+)
+target_link_directories(
+  BoltCore
+  PUBLIC
+  ${ICU_LIBRARY_DIRS}
 )
 target_compile_options(
-  bolt
+  BoltCore
   PUBLIC
   -fstandalone-debug
 )
 target_include_directories(
-  bolt
+  BoltCore
   PUBLIC
   include
+  ${ICU_LIBRARY_DIRS}
+)
+target_link_libraries(
+  BoltCore
+  PUBLIC
+  zen
+  icuuc
+)
+
+add_executable(
+  bolt
+  src/main.cc
 )
 target_link_libraries(
   bolt
   PUBLIC
-  zen
+  BoltCore
 )
 
-add_custom_command(
-  OUTPUT "${CMAKE_CURRENT_SOURCE_DIR}/include/bolt/CST.hpp" "${CMAKE_CURRENT_SOURCE_DIR}/src/CST.cc"
-  COMMAND scripts/gennodes.py --name=CST ./bolt-cst-spec.txt -Iinclude/ --include-root=bolt --source-root=src/ --namespace=bolt
-  DEPENDS scripts/gennodes.py
-  MAIN_DEPENDENCY "${CMAKE_CURRENT_SOURCE_DIR}/bolt-cst-spec.txt"
-  WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
-)
+if (BOLT_ENABLE_TESTS)
+  add_subdirectory(deps/googletest EXCLUDE_FROM_ALL)
+  add_executable(
+    alltests
+    src/TestText.cc
+  )
+  target_link_libraries(
+    alltests
+    PUBLIC
+    BoltCore
+    gtest
+    gtest_main
+  )
+endif()
+
+#add_custom_command(
+#  OUTPUT "${CMAKE_CURRENT_SOURCE_DIR}/include/bolt/CST.hpp" "${CMAKE_CURRENT_SOURCE_DIR}/src/CST.cc"
+#  COMMAND scripts/gennodes.py --name=CST ./bolt-cst-spec.txt -Iinclude/ --include-root=bolt --source-root=src/ --namespace=bolt
+#  DEPENDS scripts/gennodes.py
+#  MAIN_DEPENDENCY "${CMAKE_CURRENT_SOURCE_DIR}/bolt-cst-spec.txt"
+#  WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+#)
 
diff --git a/include/bolt/Text.hpp b/include/bolt/Text.hpp
index fb9fa61d2..7e27759ef 100644
--- a/include/bolt/Text.hpp
+++ b/include/bolt/Text.hpp
@@ -1,11 +1,13 @@
-#ifndef BOLT_TEXT_HPP
-#define BOLT_TEXT_HPP
 
-#include "ByteString.hpp"
+#pragma once
+
 #include <stddef.h>
 
+#include <vector>
 #include <string>
 
+#include "bolt/ByteString.hpp"
+
 namespace bolt {
 
   class TextLoc {
@@ -34,10 +36,25 @@ namespace bolt {
   };
 
   class TextFile {
+
+    ByteString Path;
+    ByteString Text;
+
+    std::vector<size_t> LineOffsets;
+
   public:
-    ByteString getText();
+
+    TextFile(ByteString Path, ByteString Text);
+
+    size_t getLine(size_t Offset);
+    size_t getColumn(size_t Offset);
+    size_t getStartOffset(size_t Line);
+
+    ByteString getPath() const;
+
+    ByteString getText() const;
+
   };
 
 }
 
-#endif // of #ifndef BOLT_TEXT_HPP
diff --git a/src/TestText.cc b/src/TestText.cc
new file mode 100644
index 000000000..7cf5f2465
--- /dev/null
+++ b/src/TestText.cc
@@ -0,0 +1,47 @@
+
+#include "gtest/gtest.h"
+
+#include "bolt/Text.hpp"
+
+using namespace bolt;
+
+TEST(TextFileTest, ReportsCorrectLine) {
+  TextFile T1 { "foo.txt", "bar\nbaz\nbax\n" };
+  ASSERT_EQ(T1.getLine(0), 1);
+  ASSERT_EQ(T1.getLine(1), 1);
+  ASSERT_EQ(T1.getLine(2), 1);
+  ASSERT_EQ(T1.getLine(3), 1);
+  ASSERT_EQ(T1.getLine(4), 2);
+  ASSERT_EQ(T1.getLine(5), 2);
+  ASSERT_EQ(T1.getLine(6), 2);
+  ASSERT_EQ(T1.getLine(7), 2);
+  ASSERT_EQ(T1.getLine(8), 3);
+  ASSERT_EQ(T1.getLine(9), 3);
+  ASSERT_EQ(T1.getLine(10), 3);
+  ASSERT_EQ(T1.getLine(11), 3);
+}
+
+TEST(TextFileTest, ReportsCorrectStartOffset) {
+  TextFile T1 { "foo.txt", "bar\nbaz\nbax\n" };
+  ASSERT_EQ(T1.getStartOffset(1), 0);
+  ASSERT_EQ(T1.getStartOffset(2), 4);
+  ASSERT_EQ(T1.getStartOffset(3), 8);
+  ASSERT_EQ(T1.getStartOffset(4), 12);
+  ASSERT_EQ(T1.getStartOffset(5), 12);
+}
+
+TEST(TextFileTest, ReportsCorrectColumn) {
+  TextFile T1 { "foo.txt", "bar\nbaz\nbax\n" };
+  ASSERT_EQ(T1.getColumn(0), 1);
+  ASSERT_EQ(T1.getColumn(1), 2);
+  ASSERT_EQ(T1.getColumn(2), 3);
+  ASSERT_EQ(T1.getColumn(3), 4);
+  ASSERT_EQ(T1.getColumn(4), 1);
+  ASSERT_EQ(T1.getColumn(5), 2);
+  ASSERT_EQ(T1.getColumn(6), 3);
+  ASSERT_EQ(T1.getColumn(7), 4);
+  ASSERT_EQ(T1.getColumn(8), 1);
+  ASSERT_EQ(T1.getColumn(9), 2);
+  ASSERT_EQ(T1.getColumn(10), 3);
+  ASSERT_EQ(T1.getColumn(11), 4);
+}
diff --git a/src/Text.cc b/src/Text.cc
new file mode 100644
index 000000000..17b2f05ba
--- /dev/null
+++ b/src/Text.cc
@@ -0,0 +1,49 @@
+
+#include "zen/config.hpp"
+
+#include "bolt/Text.hpp"
+#include "bolt/ByteString.hpp"
+
+namespace bolt {
+
+  TextFile::TextFile(ByteString Path, ByteString Text):
+    Path(Path), Text(Text) {
+      LineOffsets.push_back(0);
+      for (size_t I = 0; I < Text.size(); I++) {
+        auto Chr = Text[I];
+        if (Chr == '\n') {
+          LineOffsets.push_back(I+1);
+        }
+      }
+      LineOffsets.push_back(Text.size());
+    }
+
+  size_t TextFile::getStartOffset(size_t Line) {
+    return LineOffsets[Line-1];
+  }
+
+  size_t TextFile::getLine(size_t Offset) {
+    ZEN_ASSERT(Offset < Text.size());
+    for (size_t I = 0; I < LineOffsets.size(); ++I) {
+      if (LineOffsets[I] > Offset) {
+        return I;
+      }
+    }
+    ZEN_UNREACHABLE
+  }
+
+  size_t TextFile::getColumn(size_t Offset) {
+    auto Line = getLine(Offset);
+    auto StartOffset = getStartOffset(Line);
+    return Offset - StartOffset + 1 ;
+  }
+
+  ByteString TextFile::getPath() const {
+    return Path;
+  }
+
+  ByteString TextFile::getText() const {
+    return Text;
+  }
+
+}