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Rafael-SOWNet merged 1 commit into from
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The names of functions to come are refused by name #2184

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20 changes: 20 additions & 0 deletions BREAKING-CHANGES.md
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Expand Up @@ -420,6 +420,26 @@ the right shape, written out or once its operations are carried out, throws `Inv
| `"dot([1, 2], [3, 4])".ToEntity()` | throws `UnhandledParseException` | `1 * 3 + 2 * 4` |
| `"resultant(x^2 - 1, x - a, x)".ToEntity()` | throws `UnhandledParseException` | `a ^ 2 - 1` |

### The names of functions to come are refused by name

**Not silent: these names followed by a bracket now throw `UnrecognizedFunctionParseException` where they were read as
products.** An unknown name followed by a bracket is a product, so `zeta(2)` was `zeta * 2` and simplified to
`2 * zeta`. The long names of the functions the library is to have are refused until each is implemented, as `trunc`
is: `zeta`, `riemannzeta`, `hurwitzzeta`, `lambertw`, `productlog`, `mobius`, `moebiusmu`, `divisorsigma`, `primenu`,
`primeomega`, `primepi`, `harmonicnumber`, `catalannumber`, `multinomial`, `fallingfactorial`, `factorialpower`,
`risingfactorial`, `forwarddifference`, `laplacian`, `jacobian` and `hessian`. Names that will not be functions,
because what they mean differs between sources or is already written exactly, are refused with the spelling to use:
`heaviside`, `unitstep`, `isprime`, `pochhammer`, `doublefactorial`, `factorial2`, `fractionalpart` and `quotient`.
Each name without a bracket is still a variable, and short names such as `beta` and `norm` are still read as products
([#2182](https://github.com/asc-community/AngouriMath/issues/2182)).

| Input | Was (2.6.0) | Now |
|---|---|---|
| `"zeta(s)".ToEntity()` | `zeta * s` | throws `UnrecognizedFunctionParseException` |
| `"zeta(2)".ToEntity().Simplify()` | `2 * zeta` | throws `UnrecognizedFunctionParseException` |
| `"isprime(7)".ToEntity()` | `isprime * 7` | throws `UnrecognizedFunctionParseException`: write `n in PP` |
| `"heaviside(x)".ToEntity()` | `heaviside * x` | throws `UnrecognizedFunctionParseException`: write `iverson(x > 0)`, `iverson(x >= 0)` or `(1 + sgn(x))/2` |
| `"divisorsigma(k, n)".ToEntity()` | throws `UnhandledParseException` | throws `UnrecognizedFunctionParseException` |
### A subscript may have a subscript

**Not silent: what was a parse error is a name.** A name took at most one `_`, so `x_1_2` and `X_a_beta` were lexer
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44 changes: 44 additions & 0 deletions Sources/AngouriMath/Core/Antlr/AngouriMath.g
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Expand Up @@ -56,6 +56,14 @@ options
$"there is no function {name}: AngouriMath has no {what}. It is refused by name " +
$"rather than read as the product of a variable named {name} with its argument, " +
$"which is what an unknown name followed by a bracket would otherwise mean");

// A name that will not be a function, because what it means is ambiguous or is already
// written exactly another way, refused with the spelling to use, as NN is refused with ZZ+
// and ZZ*. https://github.com/asc-community/AngouriMath/issues/2182
static Entity NotAFunctionHere(string name, string instead)
=> throw new UnrecognizedFunctionParseException(
$"{name} is not a function in AngouriMath: {instead}. It is refused by name rather " +
$"than read as the product of a variable named {name} with its argument");
}

@namespace { Antlr }
Expand Down Expand Up @@ -658,6 +666,42 @@ atom returns[Entity value]
between a missing function and a wrong answer. */

| 'trunc(' args = function_arguments ')' { $value = NotImplementedFunction("trunc", "rounding functions"); }
/* Names of functions to come, reserved so that each is refused rather than read as a
product until it is implemented: zeta(s) was zeta * s. Only names no one writes as a
variable before a bracket; beta, norm, grad, div, curl and the other short ones are left
as products until each lands. The names and their conventions are in
https://github.com/asc-community/AngouriMath/issues/2182 */
| 'zeta(' args = function_arguments ')' { $value = NotImplementedFunction("zeta", "Riemann or Hurwitz zeta function yet"); }
| 'riemannzeta(' args = function_arguments ')' { $value = NotImplementedFunction("riemannzeta", "Riemann zeta function yet"); }
| 'hurwitzzeta(' args = function_arguments ')' { $value = NotImplementedFunction("hurwitzzeta", "Hurwitz zeta function yet"); }
| 'lambertw(' args = function_arguments ')' { $value = NotImplementedFunction("lambertw", "Lambert W function yet"); }
| 'productlog(' args = function_arguments ')' { $value = NotImplementedFunction("productlog", "Lambert W function yet"); }
| 'mobius(' args = function_arguments ')' { $value = NotImplementedFunction("mobius", "Mobius function yet"); }
| 'moebiusmu(' args = function_arguments ')' { $value = NotImplementedFunction("moebiusmu", "Mobius function yet"); }
| 'divisorsigma(' args = function_arguments ')' { $value = NotImplementedFunction("divisorsigma", "divisor function yet"); }
| 'primenu(' args = function_arguments ')' { $value = NotImplementedFunction("primenu", "count of distinct prime factors yet"); }
| 'primeomega(' args = function_arguments ')' { $value = NotImplementedFunction("primeomega", "count of prime factors with multiplicity yet"); }
| 'primepi(' args = function_arguments ')' { $value = NotImplementedFunction("primepi", "prime-counting function yet"); }
| 'harmonicnumber(' args = function_arguments ')' { $value = NotImplementedFunction("harmonicnumber", "harmonic numbers yet"); }
| 'catalannumber(' args = function_arguments ')' { $value = NotImplementedFunction("catalannumber", "Catalan numbers yet"); }
| 'multinomial(' args = function_arguments ')' { $value = NotImplementedFunction("multinomial", "multinomial coefficients yet"); }
| 'fallingfactorial(' args = function_arguments ')' { $value = NotImplementedFunction("fallingfactorial", "falling factorial yet"); }
| 'factorialpower(' args = function_arguments ')' { $value = NotImplementedFunction("factorialpower", "falling factorial yet"); }
| 'risingfactorial(' args = function_arguments ')' { $value = NotImplementedFunction("risingfactorial", "rising factorial yet"); }
| 'forwarddifference(' args = function_arguments ')' { $value = NotImplementedFunction("forwarddifference", "forward difference yet"); }
| 'laplacian(' args = function_arguments ')' { $value = NotImplementedFunction("laplacian", "Laplacian yet"); }
| 'jacobian(' args = function_arguments ')' { $value = NotImplementedFunction("jacobian", "Jacobian yet"); }
| 'hessian(' args = function_arguments ')' { $value = NotImplementedFunction("hessian", "Hessian yet"); }
/* Names that will not be functions, refused with the spelling to use: what they mean is
ambiguous between sources, or is already written exactly another way. */
| 'heaviside(' args = function_arguments ')' { $value = NotAFunctionHere("heaviside", "its value at 0 is 0, 1/2 or 1 by source; write iverson(x > 0), iverson(x >= 0) or (1 + sgn(x))/2"); }
| 'unitstep(' args = function_arguments ')' { $value = NotAFunctionHere("unitstep", "write iverson(x >= 0), which is 1 at 0"); }
| 'isprime(' args = function_arguments ')' { $value = NotAFunctionHere("isprime", "write n in PP"); }
| 'pochhammer(' args = function_arguments ')' { $value = NotAFunctionHere("pochhammer", "(x)_n is the rising factorial to some and the falling one to others; write risingfactorial or fallingfactorial"); }
| 'doublefactorial(' args = function_arguments ')' { $value = NotAFunctionHere("doublefactorial", "the double factorial is to be the postfix n!!, which is not implemented yet"); }
| 'factorial2(' args = function_arguments ')' { $value = NotAFunctionHere("factorial2", "the double factorial is to be the postfix n!!, which is not implemented yet"); }
| 'fractionalpart(' args = function_arguments ')' { $value = NotAFunctionHere("fractionalpart", "write x mod 1, which is in [0, 1)"); }
| 'quotient(' args = function_arguments ')' { $value = NotAFunctionHere("quotient", "write floor(a / b)"); }
| 'domain(' args = function_arguments ')'
{
Assert("domain", 2, $args.list.Count);
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60 changes: 59 additions & 1 deletion Sources/AngouriMath/Core/Antlr/AngouriMath.interp
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84 changes: 71 additions & 13 deletions Sources/AngouriMath/Core/Antlr/AngouriMath.tokens
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Expand Up @@ -196,14 +196,43 @@ T__194=195
T__195=196
T__196=197
T__197=198
NEWLINE=199
NUMBER=200
SPECIALSET=201
BOOLEAN=202
NAN=203
VARIABLE=204
COMMENT=205
WS=206
T__198=199
T__199=200
T__200=201
T__201=202
T__202=203
T__203=204
T__204=205
T__205=206
T__206=207
T__207=208
T__208=209
T__209=210
T__210=211
T__211=212
T__212=213
T__213=214
T__214=215
T__215=216
T__216=217
T__217=218
T__218=219
T__219=220
T__220=221
T__221=222
T__222=223
T__223=224
T__224=225
T__225=226
T__226=227
NEWLINE=228
NUMBER=229
SPECIALSET=230
BOOLEAN=231
NAN=232
VARIABLE=233
COMMENT=234
WS=235
'!'=1
'^'=2
'-'=3
Expand Down Expand Up @@ -398,8 +427,37 @@ WS=206
'im('=192
'imag('=193
'trunc('=194
'domain('=195
'piecewise('=196
'apply('=197
'lambda('=198
'NaN'=203
'zeta('=195
'riemannzeta('=196
'hurwitzzeta('=197
'lambertw('=198
'productlog('=199
'mobius('=200
'moebiusmu('=201
'divisorsigma('=202
'primenu('=203
'primeomega('=204
'primepi('=205
'harmonicnumber('=206
'catalannumber('=207
'multinomial('=208
'fallingfactorial('=209
'factorialpower('=210
'risingfactorial('=211
'forwarddifference('=212
'laplacian('=213
'jacobian('=214
'hessian('=215
'heaviside('=216
'unitstep('=217
'isprime('=218
'pochhammer('=219
'doublefactorial('=220
'factorial2('=221
'fractionalpart('=222
'quotient('=223
'domain('=224
'piecewise('=225
'apply('=226
'lambda('=227
'NaN'=232
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