IMP Language Lexical Analyzer

Project composed of two parts, both written using Java:

1. Parser and interpreter in JFlex
2. Parser in ANTLR Parser which reads a C-like languages, builds a AST for an IMP language and interprets the AST (including errors). For example we have this:

• input (C-like code)

int i, j, k;
i = 0;
j = 12;
while (!(i > 7)) {
	if (j > 20) {
		j = j + k;
	} else {
		j = j + 1;
	}
	i = i + 1;
}

• the AST build by the parser

<MainNode>
	<SequenceNode>
		<AssignmentNode> =
			<VariableNode> i
			<IntNode> 0
		<SequenceNode>
			<AssignmentNode> =
				<VariableNode> j
				<IntNode> 12
			<WhileNode> while
				<BracketNode> ()
					<NotNode> !
						<BracketNode> ()
							<GreaterNode> >
								<VariableNode> i
								<IntNode> 7
				<BlockNode> {}
					<SequenceNode>
						<IfNode> if
							<BracketNode> ()
								<GreaterNode> >
									<VariableNode> j
									<IntNode> 20
							<BlockNode> {}
								<AssignmentNode> =
									<VariableNode> j
									<PlusNode> +
										<VariableNode> j
										<VariableNode> k
							<BlockNode> {}
								<AssignmentNode> =
									<VariableNode> j
									<PlusNode> +
										<VariableNode> j
										<IntNode> 1
						<AssignmentNode> =
							<VariableNode> i
							<PlusNode> +
								<VariableNode> i
								<IntNode> 1

Types of nodes from AST

• MainNode - the root node of the AST and it has one child
• IntNode - a numerical value and it's a leaf node
• BoolNode - a boolean value and it's a leaf node
• VarNode - a string value, representing the name of a variable and it's a leaf node
• PlusNode
• DivNode
• BracketNode
• AndNode
• GreaterNode
• NotNode
• IfNode
• WhileNode
• AssignmentNode
• BlockNode
• SequenceNode

JFlex parser and interpreter

ANTLR parser