uce/test/script.uce

StringList script_tokenize(String code)
{
	StringList result;
	String current_token = "";
	char mode = 'N';
	char quote_character = 0;
	char last_character = 0;
	for(auto c : code)
	{
		if(mode == 'Q')
		{
			if(c == '\\')
			{

			}
			else if(quote_character == c && last_character != '\\')
			{
				mode = 'N';
				result.push_back(current_token);
				current_token = "";
			}
			else
			{
				current_token.append(1, c);
			}
		}
		else
		{
			if(isspace(c))
			{
				if(current_token != "")
					result.push_back(current_token);
				current_token = "";
			}
			else if(c == '"' || c == '\'')
			{
				mode = 'Q';
				quote_character = c;
				if(current_token != "")
					result.push_back(current_token);
				current_token = "\"";
			}
			else if(ispunct(c) && c != '_')
			{
				if(current_token != "")
					result.push_back(current_token);
				current_token = "";
				result.push_back(String().append(1, c));
			}
			else
			{
				current_token.append(1, c);
			}
		}
		last_character = c;
	}
	if(current_token != "")
		result.push_back(current_token);
	return(result);
}

struct ASTNode
{
	String identifier = "";
	String type_name = "";
	char type = 0;
	ASTNode* assign = 0;
	ASTNode* call_params = 0;
	ASTNode* children = 0;
	ASTNode* next = 0;

	ASTNode(char _type)
	{
		type = _type;
		type_name = "";
		identifier = "";
		assign = 0;
		children = 0;
		next = 0;
	}

	String to_string(String indent = "")
	{
		String result = "";
		ASTNode* current = this;
		while(current)
		{
			result += indent + String().append(1, current->type);
			if(identifier != "") result += " ident=" + identifier;
			if(type_name != "")  result += " type=" + type_name;
			result += "\n";
			if(current->call_params)
				result += current->call_params->to_string(indent + "--CALL ");
			if(current->assign)
				result += current->assign->to_string(indent + "--ASSIGN ");
			if(current->children)
				result += current->children->to_string(indent + "  ");
			current = current->next;
		}
		return(result);
	}

};

struct ParserState
{

	ASTNode* root = 0;
	StringList tokens;
	s32 token_index = 0;
	String error = "";

	String next()
	{
		return(tokens[token_index++]);
	}

	String look_ahead(u32 by)
	{
		return(tokens[token_index+by]);
	}

	bool expect(String token_str)
	{
		String found = look_ahead(0);
		if(found == token_str)
			return(true);
		token_index = tokens.size() + 1;
		error = String("'") + token_str + "' expected but '" + found + "' found";
		return(false);
	}

	void consume(String token_str)
	{
		if(expect(token_str))
			next();
	}

};

ASTNode* script_parse_expression(ParserState* state, String accept_delim);

ASTNode* script_parse_call_params(ParserState* state)
{
	ASTNode* result = new ASTNode('P');
	while(state->look_ahead(0) != ")")
	{
		state->next();
	}
	state->consume(")");
	return(result);
}

ASTNode* script_parse_expression(ParserState* state, String accept_delim)
{
	ASTNode* result = new ASTNode('E');
	String tname = state->next();
	String tnx = state->look_ahead(0);
	if(tnx == ":")
	{
		// declaration
		result->type = 'D';
		result->identifier = tname;
		state->consume(":");
		if(state->look_ahead(0) != "=")
			result->type_name = state->next();
		if(state->look_ahead(0) == "=")
		{
			state->consume("=");
			result->assign = script_parse_expression(state, accept_delim);
		}
		else
		{
			state->consume(accept_delim);
		}
		return(result);
	}
	else if(tnx == "=")
	{
		// assignment
		result->type = 'A';
		result->identifier = tname;
		state->consume("=");
		result->assign = script_parse_expression(state, accept_delim);
		return(result);
	}
	else
	{
		// who knows
		result->type = 'E';
		result->identifier = tname;
		tnx = state->look_ahead(0);
		if(tnx == "(")
		{
			result->type = 'C';
			result->call_params = script_parse_call_params(state);
		}
		state->consume(accept_delim);
		return(result);
	}
	return(result);
}

ParserState* script_parse(StringList tokens)
{
	ParserState* state = new ParserState();
	state->tokens = tokens;
	state->root = new ASTNode('R');
	ASTNode* current_node = 0;
	while(state->token_index < state->tokens.size())
	{
		if(!current_node)
		{
			current_node = script_parse_expression(state, ";");
			state->root->children = current_node;
		}
		else
		{
			current_node->next = script_parse_expression(state, ";");
			current_node = current_node->next;
		}
	}
	return(state);
}

RENDER()
{

	<>
		<link rel="stylesheet" href='style.css'></link>
		<h1>
			<a href="index.uce">UCE Test</a>:
			Script
		</h1>
	</>


	<>
		<h3>Code</h3>
		<form action="?" method="post">
			<textarea name="code"><?= first(context->post["code"]) ?></textarea>
			<input type="submit" value="parse"/>
		</form>
		<pre><?

			StringList tokens = script_tokenize(context->post["code"]);

			ParserState* ps = script_parse(tokens);

			print(ps->error+"\n");

			print(ps->root->to_string());

		?></pre>
		Params
		<pre><?= var_dump(context->params) ?></pre>
	</>

}