#ifndef _MSPH_EXPR_H
#define _MSPH_EXPR_H

/*
 * TYPES:
 * Conj
 * Disj
 * Impl
 * Arrow
 * Box
 * (Sub)
 * Forall
 * 
 * True
 * False
 * Var
 * Nominal
 *
 * Record
 *
 * DEFINITIONS/DIRECTIVES:
 * Type definition		(type A[X..] = T)
 * Nominal definition		(nominal N)
 * Member definition		(member mname : T)
 *
 * {
 * member a: A
 * member b: B
 * }
 *
 * Subtyping check		(check A <: B, checks if A <: B)
 *
 * EXTRA DEFINITIONS
 * Class definition		(class C[...] { ... }, shorthand)
 * 
 * EXPRESSIONS
 * Conj
 * Disj
 * Impl
 * Arrow
 * Box
 * (Sub)
 * Forall
 * 
 * True
 * False
 * Var
 * Nominal
 *
 * Trait			({ ... }, creates scoping)
 *
 *
 * TOKENS
 * lbrace		{
 * rbrace		}
 * lbrak		[
 * rbrak		]
 * lparen		(
 * rparen		)
 * colon		:
 * equals		=
 *
 * op_and		&
 * op_or		|
 * op_impl		=>
 * op_sub		<:
 *
 * kw_type		type
 * kw_nominal		nominal
 * kw_member		member
 * kw_check		check
 * kw_box		box
 * kw_forall		forall
 *
 * k_true		True
 * k_false		False
 *
 * ident		C, anid, ...
 *
 */

struct msph_ctx {
	int	err;
	int	err_info;
	char	errbuf[SPHO_ERR_BUF_LEN];

#ifdef SPHO_DEBUG
	char	filebuf[SPHO_ERR_FILEBUF_LEN];
	int	errline;
#endif
};

enum msph_tok_type {
	TOK_LBRACE,		// {
	TOK_RBRACE,		// }
	TOK_LBRAK,		// [
	TOK_RBRAK,		// ]
	TOK_LPAREN,		// (
	TOK_RPAREN,		// )
	TOK_COLON,		// :
	TOK_EQUALS,		// =

	TOK_AMP,		// &
	TOK_PIPE,		// |
	TOK_IMPL,		// =>
	TOK_RARROW,		// ->
	TOK_SUB,		// <:

	TOK_KW_TYPE,		// type
	TOK_KW_NOMINAL,		// nominal
	TOK_KW_MEMBER,		// member
	TOK_KW_CHECK,		// check
	TOK_KW_BOX,		// box
	TOK_KW_FORALL,		// forall

	TOK_CONST_TRUE,		// True
	TOK_CONST_FALSE,	// False

	TOK_IDENT,		// identifiers
	TOK_WSPACE,		// special: whitespace
	TOK_END			// special: denote end of array
};

#define MSPH_TOKEN_BUF_LEN	128

struct token_s {
	char	buf[MSPH_TOKEN_BUF_LEN];
};

union token_data {
	struct token_s	s;
};

struct msph_token {
	int			type;
	union token_data	d;
};

#define MSPH_FILE_NAME_LEN	1024
#define MSPH_FILE_BUF_LEN	2048
#define MSPH_TOKEN_SRC_FILE	1

struct msph_token_src_file {
	FILE		*f;

	/* circular buffer for reading */
	size_t		pos;
	size_t		end;
	char		buf[MSPH_FILE_BUF_LEN];

	/* file path */
	char		name[MSPH_FILE_NAME_LEN];
};

#define MSPH_TOKEN_SRC_STR	2
struct msph_token_src_str {
	const char	*s;
	size_t		len;
	size_t		pos;
};

union msph_token_src_data {
	struct msph_token_src_file	file;
	struct msph_token_src_str	str;
};

struct msph_token_src {
	int				type;
	union msph_token_src_data	inner;
};

struct msph_token_stream {
	struct msph_ctx		*ctx;

	struct msph_token_src	src;
};

void msph_ctx_init(struct msph_ctx *);

struct msph_token_stream	*msph_token_stream_file(struct msph_ctx *,
				    FILE *, const char *);
struct msph_token_stream	*msph_token_stream_frombuf(struct msph_ctx *,
				    const char *, size_t);

int	msph_token_stream_close(struct msph_token_stream*);

ssize_t	msph_token_stream_read_tok(struct msph_token *, size_t,
	    struct msph_token_stream *);
int	msph_token_stream_print(struct msph_token_stream *, FILE *);

ssize_t	msph_token_str(char *buf, size_t len, struct msph_token *tok);


#endif /* _MSPH_EXPR_H */