From f490cc22f589af9948fe4c2fb7099bd83f2664c7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A9r=C3=B4me=20Gu=C3=A9len?=
 <jguelen@student.42lehavre.fr>
Date: Fri, 4 Apr 2025 15:43:32 +0200
Subject: [PATCH] Parsing: Added a document to describe the underlying grammar

---
 grammar.md | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 grammar.md

diff --git a/grammar.md b/grammar.md
new file mode 100644
index 0000000..2ccae67
--- /dev/null
+++ b/grammar.md
@@ -0,0 +1,49 @@
+## Initial Grammar (Left recursivity)
+
+This grammar is conceived to take into account both left associativity
+and priority of operators to wit () is of highest priority followed by |
+and then || and && which share the same priority (priorization therefore
+occurs because of left associativity).
+
+LINE			-> CMDS eol
+CMDS			-> CMDS LIST_OP PIPELINE
+CMDS			-> PIPELINE
+PIPELINE		-> PIPELINE | GROUP_OR_SIMPLE
+PIPELINE		-> GROUP_OR_SIMPLE
+GROUP_OR_SIMPLE	-> (CMDS) REDIR
+GROUP_OR_SIMPLE -> SIMPLE
+SIMPLE			-> REDIR word REDIR SIMPLE_LST
+SIMPLE_LST		-> word REDIR SIMPLE_LST
+SIMPLE_LST		-> ε
+REDIR			-> > word REDIR
+REDIR			-> >> word REDIR
+REDIR			-> < word REDIR
+REDIR			-> << word REDIR
+REDIR			-> ε
+LIST_OP			-> &&
+LIST_OP			-> ||
+
+## Grammar after removal of left recursivity
+
+The same priorities as the previous version except it is now LL(1) and
+therefore compatible with descending syntax analysisi (LL(1)).
+
+LINE			-> CMDS eol
+CMDS			-> PIPELINE OPT_CMDS
+OPT_CMDS		-> LIST_OP PIPELINE OPT_CMDS
+OPT_CMDS		-> ε
+PIPELINE		-> GROUP_OR_SIMPLE OPT_PIPELINE
+OPT_PIPELINE	-> | GROUP_OR_SIMPLE OPT_PIPELINE
+OPT_PIPELINE	-> ε
+GROUP_OR_SIMPLE	-> (CMDS) REDIR
+GROUP_OR_SIMPLE	-> SIMPLE
+SIMPLE			-> REDIR word REDIR SIMPLE_LST
+SIMPLE_LST		-> word REDIR SIMPLE_LST
+SIMPLE_LST		-> ε
+REDIR			-> > word REDIR
+REDIR			-> >> word REDIR
+REDIR			-> < word REDIR
+REDIR			-> << word REDIR
+REDIR			-> ε
+LIST_OP			-> &&
+LIST_OP			-> ||