automated commit TP3

TP03/arith-visitor/.gitignore

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+/AritListener.py
+/AritVisitor.py

TP03/arith-visitor/Arit.g4

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+grammar Arit;
+
+prog: statement+ EOF            #statementList
+    ;
+
+statement
+    : expr SCOL                 #exprInstr
+    | 'set' ID '=' expr SCOL    #assignInstr
+    ;
+
+expr: expr multop=(MULT | DIV) expr     #multiplicationExpr
+    | expr addop=(PLUS | MINUS) expr   #additiveExpr
+    | atom                            #atomExpr
+    ;
+
+atom: INT                       #numberAtom
+    | ID                        #idAtom
+    | '(' expr ')'              #parens
+    ;
+
+
+SCOL :      ';';
+PLUS :      '+';
+MINUS :     '-';
+MULT :      '*';
+DIV :       '/';
+ID:         [a-zA-Z_] [a-zA-Z_0-9]*;
+
+INT:        [0-9]+;
+
+COMMENT:    '#' ~[\r\n]* -> skip;
+NEWLINE:    '\r'? '\n' -> skip;
+WS  :       (' '|'\t')+  -> skip;

TP03/arith-visitor/Makefile

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+PACKAGE = Arit
+MAINFILE = arit
+
+ifndef ANTLR4
+abort:
+	$(error variable ANTLR4 is not set)
+endif
+
+all: $(PACKAGE).g4
+	$(ANTLR4) $^ -Dlanguage=Python3 -visitor
+
+run: $(MAINFILE).py
+	python3 $^
+
+ex: $(MAINFILE).py
+	python3 $^ < myexample
+
+test: all
+	python3 ./test_arith_visitor.py
+
+clean:
+	find . \( -iname "~" -or -iname "*.cache*" -or -iname "*.diff" -or -iname "log.txt" -or -iname "*.pyc" -or -iname "*.tokens" -or -iname "*.interp" \) -exec rm -rf '{}' \;
+	rm -rf $(PACKAGE)*.py

TP03/arith-visitor/MyAritVisitor.py

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+from AritVisitor import AritVisitor
+from AritParser import AritParser
+
+
+class UnknownIdentifier(Exception):
+    pass
+
+
+class MyAritVisitor(AritVisitor):
+    """Visitor that evaluates an expression. Derives and overrides methods
+    from ArithVisitor (generated by ANTLR4)."""
+    def __init__(self):
+        self._memory = dict()  # store id -> values
+
+    def visitNumberAtom(self, ctx):
+        try:
+            value = int(ctx.getText())
+            return value
+        except ValueError:
+            return float(ctx.getText())
+
+    def visitIdAtom(self, ctx):
+        try:
+            return self._memory[ctx.getText()]
+        except KeyError:
+            raise UnknownIdentifier(ctx.getText())
+
+    def visitMultiplicationExpr(self, ctx):
+        # Recursive calls to children. The visitor will choose the
+        # appropriate method (visitSomething) automatically.
+        leftval = self.visit(ctx.expr(0))
+        rightval = self.visit(ctx.expr(1))
+        # an elegant way to match the token:
+        if ctx.multop.type == AritParser.MULT:
+            return leftval * rightval
+        else:
+            return leftval / rightval
+
+    def visitAdditiveExpr(self, ctx):
+        leftval = self.visit(ctx.expr(0))
+        rightval = self.visit(ctx.expr(1))
+        if ctx.addop.type == AritParser.PLUS:
+            return leftval + rightval
+        else:
+            return leftval - rightval
+
+    def visitExprInstr(self, ctx):
+        val = self.visit(ctx.expr())
+        print('The value is ' + str(val))
+
+    def visitParens(self, ctx):
+        return self.visit(ctx.expr())
+
+    def visitAssignInstr(self, ctx):
+        val = self.visit(ctx.expr())
+        name = ctx.ID().getText()
+        print('now ' + name + ' has value ' + str(val))
+        self._memory[name] = val

TP03/arith-visitor/arit.py

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+from AritLexer import AritLexer
+from AritParser import AritParser
+# from AritVisitor import AritVisitor
+from MyAritVisitor import MyAritVisitor, UnknownIdentifier
+
+from antlr4 import InputStream, CommonTokenStream
+import sys
+
+# example of use of visitors to parse arithmetic expressions.
+# stops when the first SyntaxError is launched.
+
+
+def main():
+    lexer = AritLexer(InputStream(sys.stdin.read()))
+    stream = CommonTokenStream(lexer)
+    parser = AritParser(stream)
+    tree = parser.prog()
+    print("Parsing : done.")
+    visitor = MyAritVisitor()
+    try:
+        visitor.visit(tree)
+    except UnknownIdentifier as exc:
+        print('Unknown identifier: {}'.format(exc.args[0]))
+        exit(-1)
+
+
+if __name__ == '__main__':
+    main()

TP03/arith-visitor/myexample

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+1 ;
+12 ;
+1+2 ;
+1+2*3+4;
+(1+2)*(3+4);

TP03/arith-visitor/test_arith_visitor.py

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+#!/usr/bin/env python
+from AritLexer import AritLexer
+from AritParser import AritParser
+import pytest
+from MyAritVisitor import MyAritVisitor
+
+from antlr4 import InputStream, CommonTokenStream
+import sys
+
+
+@pytest.mark.parametrize("input, expected", [
+    pytest.param('1+1;', 2),
+    pytest.param('2-1;', 1),
+    pytest.param('2*3;', 6),
+    pytest.param('6/2;', 3),
+    pytest.param('set x=42; x+1;', 43),
+    pytest.param('set x=42; set x=12; x+1;', 13)
+])
+def test_expr(input, expected):
+    lexer = AritLexer(InputStream(input))
+    stream = CommonTokenStream(lexer)
+    parser = AritParser(stream)
+    tree = parser.prog()
+    print("Parsing : done.")
+    visitor = MyAritVisitor()
+
+    def patched_visit(self, ctx):
+        self.last_expr = self.visit(ctx.expr())
+
+    visitor.visitExprInstr = patched_visit.__get__(visitor)
+    visitor.visit(tree)
+    assert visitor.last_expr == expected
+
+
+if __name__ == '__main__':
+    pytest.main(sys.argv)