From 5893afdacd1b8f37c5d8aee8ade71064747dda27 Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Fri, 17 May 2019 09:36:19 +0300
Subject: Add: example proof-of-concept code generation

---
 bindings.yaml |  8 ++++++++
 codegen.py    | 40 ++++++++++++++++++++++++++++++++++++++++
 funcs.py      |  8 ++++++++
 prelude.py    |  1 +
 scenario.txt  |  3 +++
 5 files changed, 60 insertions(+)
 create mode 100644 bindings.yaml
 create mode 100644 codegen.py
 create mode 100644 funcs.py
 create mode 100644 prelude.py
 create mode 100644 scenario.txt

diff --git a/bindings.yaml b/bindings.yaml
new file mode 100644
index 0000000..7dbe4cc
--- /dev/null
+++ b/bindings.yaml
@@ -0,0 +1,8 @@
+- pattern: given some precondition
+  function: given_precondition
+
+- pattern: when (?P<name>\S+) does something
+  function: do
+
+- pattern: then all if fine
+  function: is_fine
diff --git a/codegen.py b/codegen.py
new file mode 100644
index 0000000..6e8aac2
--- /dev/null
+++ b/codegen.py
@@ -0,0 +1,40 @@
+import json
+import re
+import sys
+import yaml
+
+
+def find_binding(binds, step):
+    for bind in binds:
+        m = re.match(bind['pattern'], step, re.I | re.M)
+        if m is not None:
+            return new_match(bind, m)
+    return None
+
+
+def new_match(bind, match):
+    return {
+        'function': bind['function'],
+        'args': match.groupdict(),
+    }
+
+
+def codegen(f, match):
+    f.write('args = {}\n'.format(json.dumps(match['args'])))
+    f.write('{}(**args)\n'.format(match['function']))
+
+
+
+with open('bindings.yaml') as f:
+    binds = yaml.safe_load(f)
+
+
+with open('prelude.py') as f:
+    sys.stdout.write(f.read())
+
+
+with open('scenario.txt') as scenario:
+    for step in scenario:
+        match = find_binding(binds, step)
+        if match is not None:
+            codegen(sys.stdout, match)
diff --git a/funcs.py b/funcs.py
new file mode 100644
index 0000000..73b11a0
--- /dev/null
+++ b/funcs.py
@@ -0,0 +1,8 @@
+def given_precondition(**kwargs):
+    print('precondition:', kwargs)
+
+def do(**kwargs):
+    print('do:', kwargs)
+
+def is_fine(**kwargs):
+    print('is_fine:', kwargs)
diff --git a/prelude.py b/prelude.py
new file mode 100644
index 0000000..30204a4
--- /dev/null
+++ b/prelude.py
@@ -0,0 +1 @@
+from funcs import *
diff --git a/scenario.txt b/scenario.txt
new file mode 100644
index 0000000..6d2fc1d
--- /dev/null
+++ b/scenario.txt
@@ -0,0 +1,3 @@
+given some precondition
+when Tomjon does something
+then all if fine
-- 
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