This document explains the SQL functions and SQL tables which are
available for the user customization in Free Hero Mesh. (You cannot
use SQL to define the rules of the game.)


=== Functions ===

Asterisks denote aggregate/window functions.

BASENAME()
  The base name, which is a copy of the first command-line argument (not
  counting the switches or the program name).

CLASS_DATA(id,info)
  Returns data about a class.

CVALUE(number)
  Makes a game value of type 'class', given the class number. You can also
  specify the class name instead of the number.

HEROMESH_ESCAPE(blob)
  Converts blob representation of a game string into escaped format.

HEROMESH_TYPE(value)
  The type of a game value, given as a 64-bit integer. The types are
  'class', 'number', 'string', 'object', and 'sound'.

HEROMESH_UNESCAPE(text)
  Converts escaped representation of a game string into text format.

LEVEL()
  The one-based order number of the current level.

LEVEL_CACHEID()
  The cache ID number of this level in the user cache table.

LEVEL_ID()
  The ID number of the current level.

LEVEL_TITLE()
  The title of the current level, as a blob.

LOAD_LEVEL(level_id)
  Only valid when Free Hero Mesh is invoked with the -x switch. Loads
  the level with the specified ID number.

MVALUE(number)
  Makes a game value of type 'message'.

MODSTATE()
  The SDL keyboard modifier state.

MOVE_LIST()
  Return the current move list as a blob.

MOVENUMBER()
  Return the number of moves executed so far since the level restarted.

NVALUE(number)
  Makes a game value of type 'number'. Same as ZERO_EXTEND.

OVALUE(number)
  Makes a game value of type 'object'. The argument is the ID number of
  the object in the OBJECTS table.

PICTURE_SIZE()
  Tell you the picture size.

READ_LUMP_AT(offset,ptr)
  Used internally; there is no way to use this in user SQL codes.

RESOURCE(...)
  Given the list of resource names, read a value from the X resource
  manager. Returns null if there is no such resource value.

SIGN_EXTEND(number)
  Sign extends a 32-bit number to 64-bits.

TRACE_OFF()
  Disables tracing when called.

TRACE_ON()
  Enables tracing when called.

XY(x,y)
  Many bindings require a position as their first argument; use this
  function to combine X/Y coordinates into a single value for this.

ZERO_EXTEND(number)
  Zero extends a 32-bit number to 64-bits. Same as NVALUE.


=== Tables ===

Asterisks denote virtual tables.

CREATE TABLE "CLASSES"("ID" INTEGER PRIMARY KEY, "NAME" TEXT, "EDITORHELP"
TEXT, "HELP" TEXT, "INPUT" INT, "QUIZ" INT, "TRACEIN" INT, "TRACEOUT" INT,
"GROUP" TEXT, "PLAYER" INT); *
  A list of classes in the current puzzle set; mostly read-only. Only
  QUIZ, TRACEIN, and TRACEOUT are writable. If TRACEIN is true then it
  will trace messages received by this class (if tracing is enabled). If
  TRACEOUT is true then it will trace messages sent by this class (if
  tracing is enabled).

CREATE TABLE "MESSAGES"("ID" INTEGER PRIMARY KEY, "NAME" TEXT, "TRACE"
INT); *
  The list of messages in the current puzzle set; mostly read-only. Only
  TRACE is writable; if true, this message will be traced.

CREATE TABLE "OBJECTS"("ID" INTEGER PRIMARY KEY, "CLASS" INT, "MISC1" INT,
"MISC2" INT, "MISC3" INT, "IMAGE" INT, "DIR" INT, "X" INT, "Y" INT, "UP"
INT, "DOWN" INT, "DENSITY" INT HIDDEN); *
  List of objects. Read-only during the game, writable in the editor.
  CLASS is a class number (the ID in the CLASSES table), DIR is the
  direction (where 0 is east, 7 is southeast), and MISC1, MISC2, MISC3
  are the game values for the initial Misc values of this object; they
  must be numbers, classes, messages, or strings. Once an object is
  created, you cannot change its class; you must delete it and then add
  a new object of the correct class. DENSITY is read-only, but you can
  use ORDER BY DENSITY to sort in the stacking order of the objects.
  UP and DOWN are also read-only.

CREATE TEMPORARY TABLE "PICTURES"("ID" INTEGER PRIMARY KEY, "NAME" TEXT
COLLATE NOCASE, "OFFSET" INT);
  List of all pictures available in this puzzle set.

CREATE TABLE "USERCACHEDATA"("ID" INTEGER PRIMARY KEY, "FILE" INT,
"LEVEL" INT, "NAME" TEXT COLLATE NOCASE, "OFFSET" INT, "DATA" BLOB,
"USERSTATE" BLOB);
  Contains the user cache data for the .level and .solution files of each
  puzzle set, in order to speed up loading and saving. The DATA will be
  null unless the data has changed, in which case the new data is stored
  here; it will later rewrite the Hamster archive with the new data and
  then it will be set to null again. USERSTATE contains user data such as
  the list of moves made by the player. FILE is the ID in the user cache
  index, and indicates which Hamster archive file this lump belongs to.
  (The USERSTATE column of this SQL table is not related to the UserState
  variable of objects in the game.)

CREATE TABLE "USERCACHEINDEX"("ID" INTEGER PRIMARY KEY, "NAME" TEXT,
"TIME" INT);
  The user cache index; contains one record for each .level and .solution
  file of all puzzle sets which have been loaded. NAME is the full path,
  and TIME is the UNIX timestamp. If you want to delete a record, then
  you should also delete all records from USERCACHEDATA whose FILE value
  is the same as the ID value in this table for which it is deleted. You
  should not touch it while Free Hero Mesh is running, though.

CREATE TEMPORARY TABLE "VARIABLES"("ID" INTEGER PRIMARY KEY, "NAME" TEXT);
  List of all global and local user variables used in the game.

