build syntax in post install script

Author: ea-rus

setup.py

@@ -1,9 +1,20 @@
 import setuptools
+from setuptools.command.install import install
 
 about = {}
 with open("mindsdb_sql_parser/__about__.py") as fp:
     exec(fp.read(), about)
 
+class PostInstallCommand(install):
+    """Post-installation for installation mode."""
+    def run(self):
+        install.run(self)
+        from mindsdb_sql_parser.parser import MindsDBParser
+        try:
+            MindsDBParser.build_to_file()
+        except Exception as e:
+            print(f'Problem with building syntax. Import might be not efficient: {e}')
+
 setuptools.setup(
     name=about['__title__'],
     version=about['__version__'],
@@ -18,5 +29,8 @@
         "Programming Language :: Python :: 3",
         "Operating System :: OS Independent",
     ],
-    python_requires=">=3.6"
+    python_requires=">=3.6",
+    cmdclass={
+        'install': PostInstallCommand,
+    }
 )

sly/yacc.py

@@ -32,7 +32,9 @@
 # -----------------------------------------------------------------------------
 
 import sys
+import os
 import inspect
+import pickle
 from collections import OrderedDict, defaultdict, Counter
 
 __all__        = [ 'Parser' ]
@@ -935,12 +937,10 @@ class LALRError(YaccError):
 # -----------------------------------------------------------------------------
 
 class LRTable(object):
-    def __init__(self, grammar):
+    def __init__(self, grammar, lr_vars=None):
         self.grammar = grammar
 
         # Internal attributes
-        self.lr_action     = {}        # Action table
-        self.lr_goto       = {}        # Goto table
         self.lr_productions  = grammar.Productions    # Copy of grammar Production array
 
         # Cache of computed gotos
@@ -962,7 +962,13 @@ def __init__(self, grammar):
         self.grammar.build_lritems()
         self.grammar.compute_first()
         self.grammar.compute_follow()
-        self.lr_parse_table()
+
+        if lr_vars is not None:
+            self.lr_action, self.lr_goto = lr_vars
+        else:
+            self.lr_action     = {}        # Action table
+            self.lr_goto       = {}        # Goto table
+            self.lr_parse_table()
 
         # Build default states
         # This identifies parser states where there is only one possible reduction action.
@@ -1985,12 +1991,36 @@ def __build_grammar(cls, rules):
         if errors:
             raise YaccError('Unable to build grammar.\n'+errors)
 
+    @classmethod
+    def _get_build_file(cls):
+        path = inspect.getfile(cls)
+        return path[: path.rfind('.')] + '.pkl'
+
+    @classmethod
+    def build_to_file(self):
+        path = self._get_build_file()
+
+        lr_table = self._lrtable
+        lr_vars = (lr_table.lr_action, lr_table.lr_goto)
+        pickle.dump(lr_vars, open(path, 'wb'))
+        print('Built to', path)
+
     @classmethod
     def __build_lrtables(cls):
         '''
         Build the LR Parsing tables from the grammar
         '''
-        lrtable = LRTable(cls._grammar)
+        # use cache
+        build_file = cls._get_build_file()
+        lr_vars = None
+        if os.path.exists(build_file):
+            try:
+                lr_vars = pickle.load(open(build_file, 'rb'))
+                assert len(lr_vars) == 2
+            except Exception:
+                pass
+
+        lrtable = LRTable(cls._grammar, lr_vars=lr_vars)
         num_sr = len(lrtable.sr_conflicts)
 
         # Report shift/reduce and reduce/reduce conflicts