Introduce critical failure type

1 files changed, 21 insertions, 0 deletions

diff --git a/README.md b/README.md
index 24b5ea6..6705ffd 100644
--- a/README.md
+++ b/README.md
@@ -7,3 +7,24 @@ The goal is to have a good enough parser generator for use in my other personal
 # The type of parsers
 
 Parsers are lambdas that receive some *input* and return either a *parsing* or a *failure*.
+
+A *parsing* denotes a successful execution of the parser on the given input.
+
+Failures can be either *normal-failure* or *critical-failure*.
+
+The distinction of failure types allows to discern between an input that needs to be
+parsed with another parser, and a syntax error.
+
+## Interaction with parser control flow
+
+### Choice (either)
+
+- parsing -> exit
+- normal-failure -> continue
+- critical-failure -> exit
+
+### Sequence (comp)
+
+- parsing -> continue
+- normal-failure -> exit
+- critical-failure -> exit