Q2 prep

Q2/Artefacts/TreesUser.py

@@ -0,0 +1,27 @@
+from antlr4.Utils import escapeWhitespace
+from antlr4.tree.Tree import Tree
+from antlr4.tree.Trees import Trees
+
+# need forward declaration
+Parser  = None
+
+class TreesUser(Trees):
+
+    # Print out a whole tree in prettier form
+    # Based on Trees.toStringTree()
+    # indent is the number of indents to use in the display
+    @classmethod
+    def PrettyPrint(cls, t:Tree, ruleNames:list=None, recog:Parser=None, indent:int=0):
+        # indentation is the indent to actually display
+        indentation = ''
+        for n in range(indent):
+            indentation += '   '
+        if recog is not None:
+            ruleNames = recog.ruleNames
+        s = escapeWhitespace(cls.getNodeText(t, ruleNames), False)
+        retval = indentation + s + "\n"
+        if t.getChildCount()>0:
+            # we have children to deal with
+            for i in range(0, t.getChildCount()):
+                retval += cls.PrettyPrint(t.getChild(i), ruleNames, indent=indent+1)
+        return retval

Q2/Artefacts/fspow.g4

@@ -0,0 +1,62 @@
+grammar fspow;
+// workshop 4 version
+
+prog:   stat+ ;
+
+// labelling alternatives creates extra visitor methods
+// the labels migh clash with rule names, so I make them unique
+stat:
+        assignment      # statAssignment 
+    |   fcList          # statFcList
+    |   fcApplySelector # statFcApplySelector
+    |   message         # statMessage
+    ;
+
+assignment :
+    ID '=' expression ;
+    
+// when alternatives are introduced, try using labels to distinguish
+expression : 
+    ID              # exprID
+    |
+    selCreation     # exprSelCreation 
+    |
+    fcCreation   # exprFcCreation
+    ;
+// -------
+// filecollection statements    
+// -------
+fcCreation:         fcCreationName '(' rootSpecifier ')' ;
+
+fcCreationName:     'FileCollection' ;
+rootSpecifier:      STRING ;
+// -------
+// selector statements    
+// -------
+selCreation :       selCreationName '(' filterSpecifier ')' ;
+
+selCreationName:    'Selector' ; 
+filterSpecifier:    selfilter '(' STRING ')' ;
+selfilter:          'name' ;     
+// -------
+// apply statement    
+// -------
+fcApplySelector:    ID '.' applyName '(' expression ')' ;
+
+applyName:          'apply' ;
+// -------
+// print statement    
+// -------
+fcList:             ID '.' printName ;
+
+printName:          'print()' ;
+// -------
+// message statement    
+// -------
+message: 'message' STRING ;
+
+ID:         [a-zA-Z][a-zA-Z0-9]* ;
+STRING:     '"'.*?'"'     
+    {self.text = self.text[1:-1]} ;
+WS :        [ \t\r\n]+ -> skip ;
+COMMENT :   '//' ~[\r\n]* -> channel(HIDDEN) ;

Q2/Artefacts/fspow.py

@@ -0,0 +1,64 @@
+# main.py
+"""
+Parse and execute statements either in stdin or in file
+"""
+
+import sys
+
+from antlr4 import *
+from fspowLexer import fspowLexer
+from fspowParser import fspowParser
+# from fspowListener import fspowListener
+# from antlr4.tree.Trees import Trees
+from TreesUser import TreesUser
+from Q2.Artefacts.fspowVisitorUser import fspowVisitorUser
+
+
+def main(argv):
+    # argv[1] s/be name of source file
+    # if missing, use stdin
+    if len(argv) == 1:
+        # StdinStream is a standard ANTLR class read by the lexer
+        # (It is not a file descriptor)        
+        inpstream = StdinStream()
+    else:
+        inpname = argv[1]
+        # FileStream is a standard ANTLR class read by the lexer
+        # (It is not a file descriptor)        
+        inpstream = FileStream(inpname)
+
+    
+
+    # The lexer analyses the characters on inpstream and produces tokens 
+    lexer = fspowLexer(inpstream)
+    # .. on the token stream (belonging to a standard ANTLR class)
+    tokstream = CommonTokenStream(lexer)
+
+    # The parser produces an abstract syntax tree
+    parser = fspowParser(tokstream)
+    # When we execute the parse, we need to give it the starting rule of our grammar,
+    # which in our case is 'start' (as defined in fspow.g4),
+    # so here we invoke the method named after this rule: start()
+    tree = parser.prog()
+    
+    # print the parse tree
+    #print(TreesUser.toStringTree(tree, None, parser))
+    print(TreesUser.PrettyPrint(tree, None, parser))
+
+    visitor = fspowVisitorUser()
+    visitor.visit(tree)
+    
+    # The listener defines the actions to take upon entering an exiting nodes for 
+    # specific tokens on the AST
+    # listener = fspowListener()
+    
+    # A ParseTreeWalker is annother standard ANTLR class, that performs a walk on the AST
+    # walker = ParseTreeWalker()
+
+    # Get the tree walker to perform a walk on the AST, getting the listener to perform
+    # the appropriate actions
+    # walker.walk~(listener, tree)
+
+
+if __name__ == '__main__':
+    main(sys.argv)

Q2/Artefacts/fspowVisitorUser.py

@@ -0,0 +1,36 @@
+# Generated from fspow.g4 by ANTLR
+from antlr4 import *
+#from idlelib.idle_test.test_configdialog import root
+if __name__ is not None and "." in __name__:
+    from .fspowParser import fspowParser
+else:
+    from fspowParser import fspowParser
+
+# superclass
+from fspowVisitor import fspowVisitor
+
+# our own imports:
+from repertoire.FileCollection import *
+from repertoire.Selector import *
+from repertoire.FSObject import *
+
+# for symbol table
+from collections import defaultdict
+
+# This class defines a complete specific visitor for a parse tree produced by fspowParser.
+
+class fspowVisitorUser(fspowVisitor):
+    
+    # where all the variables reside
+    variablesTable = defaultdict()
+
+    
+    # just write methods to be overridden
+    # in future, may want to implement multiple subclasses
+    # but for now, I'd copy the ones I need to override here to implement them
+    
+
+
+del fspowParser
+
+

Q2/Artefacts/mincommands.txt

@@ -0,0 +1,15 @@
+message "Hello world!"
+// wombats = FileCollection("wombats")
+// wombats.print()
+// hairies = Selector(name("hairy")) 
+// wombats.apply(hairies)
+// the following not yet implemented
+// wombats.apply(Selector(name("")))
+// wombats.print()
+// marsupials = FileCollection("marsupials")
+// marsupials.print()
+
+
+
+
+