diff --git a/README.md b/README.md
index c31353071..ac6fbeb35 100644
--- a/README.md
+++ b/README.md
@@ -65,7 +65,12 @@ Windows users should get Windows Subsystem for Linux a.k.a WSL (recommended) or
 
 * Install right [switch](https://opam.ocaml.org/doc/Manual.html#Switches) for OCaml compiler
 
-  `opam switch create lama ocaml-variants.4.10.1+flambda`
+    ```
+    # for fresh opam 
+    opam switch create 4.14.0+flambda --packages=ocaml-variants.4.14.0+options,ocaml-option-flambda 
+    # for old opam 
+    opam switch create lama ocaml-variants.4.10.1+flambda   
+    ```
 
   In above command:
 
diff --git a/spec/.gitignore b/spec/.gitignore
index c78b14e25..99dcfd7ea 100644
--- a/spec/.gitignore
+++ b/spec/.gitignore
@@ -1 +1,5 @@
 commitdate.tex
+*.log
+*.out
+*.synctex.gz
+*.toc
\ No newline at end of file
diff --git a/spec/01.introduction.tex b/spec/01.introduction.tex
index 2022b01c6..962a76991 100644
--- a/spec/01.introduction.tex
+++ b/spec/01.introduction.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \chapter{Introduction}
 
 \lama is a programming language developed by JetBrains Research for educational purposes as an exemplary language to introduce
diff --git a/spec/03.01.lexical_structure.tex b/spec/03.01.lexical_structure.tex
index abdd3f5aa..435689a0c 100644
--- a/spec/03.01.lexical_structure.tex
+++ b/spec/03.01.lexical_structure.tex
@@ -1,3 +1,7 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
+
 \section{Lexical Structure}
 \label{sec:lexical_structure}
 
diff --git a/spec/03.02.compilation_units.tex b/spec/03.02.compilation_units.tex
index 8433dc5e2..beb4c998d 100644
--- a/spec/03.02.compilation_units.tex
+++ b/spec/03.02.compilation_units.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \FloatBarrier
 
 \begin{figure}[t]
diff --git a/spec/03.03.scope_expressions.tex b/spec/03.03.scope_expressions.tex
index 09259be1f..631e7a792 100644
--- a/spec/03.03.scope_expressions.tex
+++ b/spec/03.03.scope_expressions.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \begin{figure}[t]
   \[
     \begin{array}{rclc}
diff --git a/spec/03.04.expressions.tex b/spec/03.04.expressions.tex
index 0d1f95bb5..db9c875e6 100644
--- a/spec/03.04.expressions.tex
+++ b/spec/03.04.expressions.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \section{Expressions}
 \label{sec:expressions}
 
@@ -37,7 +40,7 @@ property ``$e$ is a reference''. The result of assignment operator coincides wit
 assigns 3 to both "\lstinline|x|" and "\lstinline|y|".
 
 \begin{figure}[h]
-  \newcommand{\Ref}[1]{\mathcal{R}\,({#1})}
+  \renewcommand{\Ref}[1]{\mathcal{R}\,({#1})}
   \renewcommand{\arraystretch}{4}
   \[
     \begin{array}{cc}
diff --git a/spec/04.extensions.tex b/spec/04.extensions.tex
index cbd0937d9..a0ea35174 100644
--- a/spec/04.extensions.tex
+++ b/spec/04.extensions.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \chapter{Extensions}
 \label{sec:extensions}
 
diff --git a/spec/05.driver_options.tex b/spec/05.driver_options.tex
index e19958d4e..3f484df8c 100644
--- a/spec/05.driver_options.tex
+++ b/spec/05.driver_options.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \chapter{Driver Options and Separate Compilation}
 \label{sec:driver}
 
diff --git a/spec/06.limitations.tex b/spec/06.limitations.tex
index ae351de48..28dff93a9 100644
--- a/spec/06.limitations.tex
+++ b/spec/06.limitations.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \chapter{Implementation-dependent Limitations}
 \label{sec:limitations}
 
diff --git a/spec/07.debugging.tex b/spec/07.debugging.tex
index 7037aea7b..f6c28c386 100644
--- a/spec/07.debugging.tex
+++ b/spec/07.debugging.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \chapter{Debugging Support}
 \label{sec:debugging}
 
diff --git a/spec/08.standard_library.tex b/spec/08.standard_library.tex
index 30bed42e4..5ca12f9f5 100644
--- a/spec/08.standard_library.tex
+++ b/spec/08.standard_library.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \chapter{Standard Library}
 \label{sec:stdlib}
 
diff --git a/spec/lama-spec.tex b/spec/lama-spec.tex
index 71b33dbf9..6bef1986f 100644
--- a/spec/lama-spec.tex
+++ b/spec/lama-spec.tex
@@ -1,3 +1,6 @@
+% !TEX TS-program = pdflatex
+% !TeX spellcheck = en_US
+% !TEX root = lama-spec.tex
 \documentclass{book}
 
 \newcommand\hmmax{0}