The main new finction is is(), which tests the type of a value. There
are also constants for each of the possible token types, and one new
conversion: number(), which converts a value into the most appropriate number
type. This change also reuses the functions in scanner.h for exracting ints,
floats, and identifiers from strings, rather than either rewriting the
functionality elsewhere, or using the general-purpose scan when only one
token type was of interest.
For clarity, it is valuable for the results of comparisons to show as "true"
and "false" rather than "1" and "0". This change implements a BOOL type
to facilitate that. Since we want logical operators to short-circuit, this
change also obliges the introduction of macros, which are just like functions
except their arguments are not evaluated before control is passed to the
routine implementing the macro.
This change is the "easy" part of #64, but to reduce the amount of duplicated
code, this change also modifies the internals of implementing a function.
The function identifier is now passed to the implementation as well, allowing
many implementations of similar functions to be collapsed more easily.
There turned out to be one blocking technical issue for full adpotion of
tpa format, and that was the fact that the printed representation of
floating values inside the tpa file might not reproduce the same double
when read. This change therefore introduces the "hexact" floating point
format, based on the the %La format string, which produces a hex
representation with exact round trips. While working on this, it was
convenient to add a new representation "compact" which is basically the
shorter of decimal and scientific representations, without trailing zeros.
This is now the default float format, but of course one can select decimal
or scientific formats to restore prior appearance. However, full-precision
compact format is now the (only) format for editing cell contents, as it
is accurate and efficient. Of course you can enter floating point values
in any format you like when typing in a formula.
The addition of several new floating point options overloaded the menus
in terminal teapot, so this change also revamps those menus slightly,
including eliminating the unused MenuChoice struct, and just specifying menus
with an array of strings.
Closes#63.
The primary change is to add a “funcall” token, so that an entire expression
can be encapsulated as a single token. This change is used to allow a cell to
include simply a selection of appropriate semantic tokens. I.e., the content
and iterative content are now each a single token like the value and the
result value. Token vectors are used only as intermediate results in scanning
and parsing.
Not this means the cells are now in effect storing parse trees, so
computation should be slightly faster and future extensions (like #56) should
be facilitated.
This commit also takes the opportunity while internals are being altered to
add another token to a cell for future use for computed attributes, cf #22,
and to change the internal numerical values from double and ints to long
doubles and long longs. However, the change attempts to encapsulate that
choice so it would be easy to change back or change to another representation.
Note that these changes break savexdr(), as the internal binary format of
a cell is now different. Rather than reimplement it, it is deprecated as
the world does not need another binary spreadsheet format. Hence, the
ascii format for teapot spreadsheets becomes the primary file format.
Loading of old xdr files is still supported for backward compatibility.
Closes#59.
Also along the way, various other slight fixes and enhancements crept in,
a partial but probably not exhaustive list of which follows:
Fixes#31.
Further revisions and improvements to documentation.
Make the approximate comparison of floating point values scale more
accurately with the size of the doubles being compared.
Further extensions of absolute and relative cell addressing.
Addition of (circle constant) tau function/constant.
Modified string conversion to simply use internal printing routines, and
to take "scientific" and "decimal" keywords.
Allowed n() function to take a list of values, or just a single location
defaulting to the current location.
Added floor, ceil, trunc, and round functions, and allowed them to be
keywords controlling the int() integer conversion function as well.
Allowed substr() to drop its last argument to go to the end of the string.
Provided an enum of built-in functions to preserve legacy function
identifiers, allowing the large table inside func.c to be reorganized
in a clearer fashion.
Added additional annotation of properties of the built-in functions,
including precedence.
All operators are now also accessible as built-in functions.
Made precedence of unary - lower than ^ to match python.
Avoided inadvertently using FLTK @symbol abbreviations for formulas with
"@" in them.
Prior to this change, every evaluation re-parses the expression. The
intermediate form as a parse tree is never stored anywhere. This change
adds a new token type, FUNCALL, which acts as a node in a parse tree, and
adds an (untested) evaluation method which returns the unevaluated parse tree
as opposed to evaluating as it goes.
This is preparation for a following step in which rather than storing a token
sequence for each variety of content, teapot will store a single token
representing the parse tree, allowing for quicker evaluation when the time
comes; no actual parsing will have to occur on evaluation.
Also a small amount of preparation of storing parse trees instead of
linear sequences of tokens got mixed in here, namely a new type of
token called a "FUNCALL".
The new function is X(SRC,REF), which briefly for a cell in the neighborhood
of REF returns the corresponding cell in the neighborhood in SRC. For
further details, see the updated documention.
In developing and documenting this function, I refined some of the
existing error messages (e.g. showing the coordinates when there is an
attempt to obtain a cell with a negative coordinate) and improved the
error propagation to increase the chance that the innermost error will
percolate to the top level.
Glen Whitney