diff --git a/AutoBlueprint/Latex/Basic.lean b/AutoBlueprint/Latex/Basic.lean
new file mode 100644
index 0000000..3d5ad0a
--- /dev/null
+++ b/AutoBlueprint/Latex/Basic.lean
@@ -0,0 +1,315 @@
+-- import Mathlib.ModelTheory.Basic
+import Mathlib.Tactic.Linarith
+
+section
+
+def ite_lt [LT α] {x y : α} {flag : Prop} [Decidable flag] {z : α} (h₁ : x < z) (h₂ : y < z)
+    : (if flag then x else y) < z := by
+  by_cases hf : flag <;> {simp only [hf]; assumption}
+
+private def parse_line? (line : String) (field : String) : Option String :=
+  let line := line.trim
+  if line.startsWith ("\\" ++ field ++ "{") && line.endsWith "}" then
+    let value := String.mk line.data.toArray[field.length + 2:line.length - 1].toArray.toList
+    if value.length > 0 then some value else none
+  else none
+
+private def parse_first_line? (line : String) : Option String :=
+  parse_line? line "begin"
+
+private def parse_last_line? (line : String) : Option String :=
+  parse_line? line "end"
+
+private def parse_label? (line : String) : Option String :=
+  parse_line? line "label"
+
+private def parse_name? (line : String) : Option String :=
+  parse_line? line "lean"
+
+private def parse_uses? (line : String) : Option (List String) :=
+  let content := parse_line? line "uses"
+  match content with
+  | none => none
+  | some content =>
+    let lst := List.map String.trim (content.splitOn ",")
+    some lst
+
+private def parse_content (lines : List String) : String :=
+  String.intercalate "\n" (lines.filter (fun line => ¬ line.startsWith "\\"))
+
+private def split_environments? (s : String) : Option (String × String) :=
+  let lines := List.map String.trim (s.splitOn "\n")
+  let begins := List.findIdxs (fun line => not (parse_first_line? line).isNone) lines
+  let ends := List.findIdxs (fun line => not (parse_last_line? line).isNone) lines
+  match hb : begins.length, he : ends.length with
+  | 2, 2 =>
+    let begin₁ := begins[0]
+    let end₁ := ends[0]
+    let begin₂ := begins[1]
+    let end₂ := ends[1]
+    some ⟨String.intercalate "\n" (lines.toArray[begin₁:end₁ + 1].toArray.toList),
+          String.intercalate "\n" (lines.toArray[begin₂:end₂ + 1].toArray.toList)⟩
+  | _, _ => none
+
+
+end
+
+structure EnvironmentWithoutProof where
+  type : String
+  leanok : Bool
+  uses : List String
+  content : String
+
+namespace EnvironmentWithoutProof --region
+
+instance : ToString EnvironmentWithoutProof where
+  toString env :=
+    "\\begin{" ++ env.type ++ "}\n" ++
+    (if env.leanok then "\\leanok\n" else "") ++
+    "\\uses{" ++ (String.intercalate ", " env.uses) ++ "}\n" ++
+    env.content ++ "\n" ++
+    "\\end{" ++ env.type ++ "}\n"
+
+def parse? (s : String) : Option EnvironmentWithoutProof :=
+  let lines := List.map String.trim (s.splitOn "\n")
+  let len := lines.length
+  match h : len with
+  | 0 | 1 | 2 => none
+  | n + 3 =>
+    let type_first? := parse_first_line? lines[0]
+    let type_last? := parse_last_line? lines[len - 1]
+    match type_first?, type_last? with
+    | _, none | none, _ => none
+    | some type, some type' =>
+      if type ≠ type' then none else
+        let leanok := lines[1] == "\\leanok"
+        let uses_idx := if leanok then 2 else 1
+        let uses? := parse_uses? (lines[uses_idx]'(by apply ite_lt <;> linarith))
+        match uses? with
+        | none => none
+        | some uses =>
+          let content := parse_content lines
+          some {type := type, leanok := leanok, uses := uses, content := content}
+
+end EnvironmentWithoutProof --end
+
+structure ProofEnvironment where
+  leanok : Bool
+  uses : List String
+  content : String
+
+def EnvironmentWithoutProof.toProofEnvironment {env : EnvironmentWithoutProof} (_ : env.type = "proof")
+    : ProofEnvironment :=
+  {leanok := env.leanok, uses := env.uses, content := env.content}
+
+namespace ProofEnvironment --region
+
+def toEnvironmentWithoutProof (env : ProofEnvironment) : EnvironmentWithoutProof :=
+  {env with type := "proof"}
+
+instance : Coe ProofEnvironment EnvironmentWithoutProof where
+  coe env := env.toEnvironmentWithoutProof
+
+instance : ToString ProofEnvironment where
+  toString env := toString (env : EnvironmentWithoutProof)
+
+def parse? (s : String) : Option ProofEnvironment :=
+  let env? := EnvironmentWithoutProof.parse? s
+  match env? with
+  | none => none
+  | some env =>
+  if h : env.type ≠ "proof" then none else
+  some $ env.toProofEnvironment (by push_neg at h; exact h)
+
+end ProofEnvironment --end
+
+structure EnvironmentWithProof where
+  type : String
+  label : String
+  name : String
+  leanok : Bool
+  uses : List String
+  content : String
+  proof : ProofEnvironment
+
+namespace EnvironmentWithProof --region
+
+instance : ToString EnvironmentWithProof where
+  toString env :=
+    "\\begin{" ++ env.type ++ "}\n" ++
+    "\\label{" ++ env.label ++ "}\n" ++
+    "\\lean{" ++ env.name ++ "}\n" ++
+    (if env.leanok then "\\leanok\n" else "") ++
+    "\\uses{" ++ (String.intercalate ", " env.uses) ++ "}\n" ++
+    env.content ++ "\n" ++
+    "\\end{" ++ env.type ++ "}\n" ++
+    toString env.proof
+
+def parse? (s : String) : Option EnvironmentWithProof :=
+  let s? := split_environments? s
+  match s? with
+  | none => none
+  | some (s₁, s₂) =>
+  let lines := List.map String.trim (s₁.splitOn "\n")
+  let len := lines.length
+  match h : len with
+  | 0 | 1 | 2 | 3 | 4 => none
+  | n + 5 =>
+  let type_first? := parse_first_line? lines[0]
+  let type_last? := parse_last_line? lines[len - 1]
+  match type_first?, type_last? with
+  | _, none | none, _ => none
+  | some type, some type' =>
+  if type ≠ type' then none else
+    let label? := parse_label? lines[1]
+    match label? with
+    | none => none
+    | some label =>
+    let name? := parse_name? lines[2]
+    match name? with
+    | none => none
+    | some name =>
+    let leanok := lines[3] == "\\leanok"
+    let uses_idx := if leanok then 4 else 3
+    let uses? := parse_uses? (lines[uses_idx]'(by apply ite_lt <;> linarith))
+    match uses? with
+    | none => none
+    | some uses =>
+    let content := parse_content lines
+    let proof? := ProofEnvironment.parse? s₂
+    match proof? with
+    | none => none
+    | some proof =>
+    some {type := type, label := label, name := name, leanok := leanok,
+          uses := uses, content := content, proof := proof}
+
+end EnvironmentWithProof --end
+
+structure TheoremEnvironment where
+  label : String
+  name : String
+  leanok : Bool
+  uses : List String
+  content : String
+  proof : ProofEnvironment
+
+def EnvironmentWithProof.toTheoremEnvironment {env : EnvironmentWithProof} (_ : env.type = "theorem")
+    : TheoremEnvironment :=
+  {label := env.label, name := env.name, leanok := env.leanok,
+   uses := env.uses, content := env.content, proof := env.proof}
+
+namespace TheoremEnvironment --region
+
+def toEnvironmentWithProof (env : TheoremEnvironment) : EnvironmentWithProof :=
+  {env with type := "theorem"}
+
+instance : Coe TheoremEnvironment EnvironmentWithProof where
+  coe := toEnvironmentWithProof
+
+instance : ToString TheoremEnvironment where
+  toString env := toString (env : EnvironmentWithProof)
+
+def parse? (s : String) : Option TheoremEnvironment :=
+  let env? := EnvironmentWithProof.parse? s
+  match env? with
+  | none => none
+  | some env =>
+  if h : env.type ≠ "theorem" then none else
+  some $ env.toTheoremEnvironment (by push_neg at h; exact h)
+
+end TheoremEnvironment --end
+
+structure LemmaEnvironment where
+  label : String
+  name : String
+  leanok : Bool
+  uses : List String
+  content : String
+  proof : ProofEnvironment
+
+def EnvironmentWithProof.toLemmaEnvironment {env : EnvironmentWithProof} (_ : env.type = "lemma")
+    : LemmaEnvironment :=
+  {label := env.label, name := env.name, leanok := env.leanok,
+    uses := env.uses, content := env.content, proof := env.proof}
+
+namespace LemmaEnvironment --region
+
+def toEnvironmentWithProof (env : LemmaEnvironment) : EnvironmentWithProof :=
+  {env with type := "theorem"}
+
+instance : Coe LemmaEnvironment EnvironmentWithProof where
+  coe env := env.toEnvironmentWithProof
+
+instance : ToString LemmaEnvironment where
+  toString env := toString (env : EnvironmentWithProof)
+
+def parse? (s : String) : Option LemmaEnvironment :=
+  let env? := EnvironmentWithProof.parse? s
+  match env? with
+  | none => none
+  | some env =>
+  if h : env.type ≠ "lemma" then none else
+  some $ env.toLemmaEnvironment (by push_neg at h; exact h)
+
+end LemmaEnvironment --end
+
+namespace BlueprintLatex.Test --region
+
+def env₁ : ProofEnvironment where
+  leanok := false
+  uses := ["thm:merhaba"]
+  content := "This is a proof."
+
+def env₂ : TheoremEnvironment where
+  label := "thm:current_theorem"
+  name := "FirstOrder.Language.mytheorem"
+  leanok := true
+  uses := ["thm:old-theorem", "lem:old-lemma", "def:old-definition"]
+  content := "This is a very important theorem."
+  proof := env₁
+
+#eval env₁
+#eval env₂
+
+open EnvironmentWithoutProof
+
+def test_parse_line? : IO Unit := do
+  let line := "\\begin{merhaba}"
+  IO.println (parse_line? line "begin")
+
+def test_parse₁? : IO Unit := do
+  let stream ← IO.FS.Handle.mk "proof.tex" IO.FS.Mode.read
+  let s ← stream.readToEnd
+  let env? := parse? s
+  match env? with
+  | none => IO.println "No environment found"
+  | some env =>
+    IO.println $ "type: " ++ env.type
+    IO.println $ "leanok: " ++ reprStr env.leanok
+    IO.println $ "uses: " ++ env.uses.toString
+    IO.println $ "content: " ++ env.content
+
+def test_splitEnvironment? : IO Unit := do
+  let stream ← IO.FS.Handle.mk "theorem.tex" IO.FS.Mode.read
+  let s ← stream.readToEnd
+  let envs? := split_environments? s
+  match envs? with
+  | none => IO.println "No environments found"
+  | some (env₁, env₂) => do
+    IO.println env₁
+    IO.println env₂
+
+def test_parse?_theorem : IO Unit := do
+  let stream ← IO.FS.Handle.mk "theorem.tex" IO.FS.Mode.read
+  let s ← stream.readToEnd
+  let env? := TheoremEnvironment.parse? s
+  match env? with
+  | none => IO.println "No theorem found"
+  | some env => IO.println env
+
+#eval test_parse_line?
+#eval test_parse₁?
+#eval test_splitEnvironment?
+#eval test_parse?_theorem
+
+end BlueprintLatex.Test --end