Quote/literal concatenation #56

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glen · 2019-08-19T19:27:56Z

glen commented

2019-08-19 19:27:56 +00:00

Need a special function symbol, ideally ‘, which quotes expressions. So the value of ‘min(3,4) is the funcall expression min(3,4), rather than the computed value 3. This will have to have a special shortcut in parser.c. This way, the special semantics of eval can be eliminated, because we can make the value of another cell be an expression.

As an additional idea, ‘ with more than one argument can stand in as a “literal concatenation” of values of disparate token types. Thus, if not all of its arguments are strings, the "concat" function would produce one of these ‘-expressions as its value. They would print the same way, by concatenating the print representation of all of their arguments. An advantage of this additional idea is if there were style tokens (see #55) in the list of items being literally concatenated, when they were emitted they could alter the style being produced mid-value.

Need a special function symbol, ideally ‘, which quotes expressions. So the value of ‘min(3,4) is the funcall expression min(3,4), rather than the computed value 3. This will have to have a special shortcut in parser.c. This way, the special semantics of eval can be eliminated, because we can make the value of another cell be an expression. As an additional idea, ‘ with more than one argument can stand in as a “literal concatenation” of values of disparate token types. Thus, if not all of its arguments are strings, the "concat" function would produce one of these ‘-expressions as its value. They would print the same way, by concatenating the print representation of all of their arguments. An advantage of this additional idea is if there were style tokens (see #55) in the list of items being literally concatenated, when they were emitted they could alter the style being produced mid-value.

glen commented

2019-08-19 19:42:27 +00:00

Quite possibly this quote/literal concatenation should be a distinct token type, as it is handled differently in eval, etc.

glen referenced this issue from a commit

2019-08-23 19:23:00 +00:00

Streamline internals of teapot 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.

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