diff options
Diffstat (limited to 'src/generators.erl')
| -rw-r--r-- | src/generators.erl | 73 |
1 files changed, 48 insertions, 25 deletions
diff --git a/src/generators.erl b/src/generators.erl index 9e682d3..37facc3 100644 --- a/src/generators.erl +++ b/src/generators.erl @@ -25,18 +25,18 @@ %%% </ul> %%% %%% Function relations reference domain relations in their schemas: -%%% ``` -%%% schema => #{a => integers, b => integers, sum => integers} -%%% ''' +%%% <pre> +%%% schema => #{a => integers, b => integers, sum => integers} +%%% </pre> %%% %%% == Reversibility == %%% %%% Function relations support bidirectional querying (like Prolog): %%% <ul> -%%% <li>`Plus[1, 2, ?]' → ? = 3 (forward)</li> -%%% <li>`Plus[1, ?, 3]' → ? = 2 (backward, solve for b)</li> -%%% <li>`Plus[?, 2, 3]' → ? = 1 (backward, solve for a)</li> -%%% <li>`Plus[?, ?, 5]' → all pairs (a,b) where a+b=5</li> +%%% <li>Plus[1, 2, ?] yields ? = 3 (forward)</li> +%%% <li>Plus[1, ?, 3] yields ? = 2 (backward, solve for b)</li> +%%% <li>Plus[?, 2, 3] yields ? = 1 (backward, solve for a)</li> +%%% <li>Plus[?, ?, 5] yields all pairs (a,b) where a+b=5</li> %%% </ul> %%% %%% The generators use constraint analysis to determine which arguments @@ -45,9 +45,9 @@ %%% == Relational Composition == %%% %%% In the future, function relations will be used through joins: -%%% ``` +%%% <pre> %%% Integer[A], Integer[B], Plus[A, B, Sum] -%%% ''' +%%% </pre> %%% %%% This corresponds to a three-way join where the join conditions %%% provide the constraints to each relation. @@ -62,12 +62,13 @@ -include("operations.hrl"). -export([ - naturals/1, - integers/1, - rationals/1, + boolean/1, + natural/1, + integer/1, + rational/1, make_range_generator/3, - constrained_naturals/2, - constrained_integers/2, + constrained_natural/2, + constrained_integer/2, %% Function relations plus/1, times/1, @@ -79,6 +80,28 @@ %%% Primitive Generators %%% ============================================================================ +%% @doc Generator for boolean domain (𝔹 = {true, false}). +%% +%% Generates the two boolean values. This is a finite immutable relation. +%% If constraints specify equality, only generates that value. +%% +%% @param Constraints Map of attribute constraints +%% @returns Generator function producing booleans +boolean(Constraints) -> + case maps:get(value, Constraints, unbounded) of + {eq, true} -> + make_singleton_generator(#{value => true}); + {eq, false} -> + make_singleton_generator(#{value => false}); + {in, Values} -> + %% Filter to only boolean values + BoolValues = [V || V <- Values, V =:= true orelse V =:= false], + make_membership_generator(BoolValues, fun(V) -> #{value => V} end); + _ -> + %% Enumerate all booleans: true, false + make_membership_generator([true, false], fun(V) -> #{value => V} end) + end. + %% @doc Generator for natural numbers (ℕ = {0, 1, 2, 3, ...}). %% %% Enumerates natural numbers starting from 0. If constraints specify a range, @@ -86,7 +109,7 @@ %% %% @param Constraints Map of attribute constraints %% @returns Generator function producing naturals -naturals(Constraints) -> +natural(Constraints) -> case extract_bounds(Constraints, value) of {range, Min, Max} when Min >= 0 -> make_range_generator(Min, Max, fun(N) -> #{value => N} end); @@ -130,7 +153,7 @@ naturals(Constraints) -> %% %% @param Constraints Map of attribute constraints %% @returns Generator function producing integers -integers(Constraints) -> +integer(Constraints) -> case extract_bounds(Constraints, value) of {range, Min, Max} -> make_integer_range_generator(Min, Max); @@ -158,7 +181,7 @@ integers(Constraints) -> %% %% @param Constraints Map of attribute constraints %% @returns Generator function producing rationals -rationals(Constraints) -> +rational(Constraints) -> %% Stern-Brocot tree enumeration %% Start with mediant tree: 0/1, 1/1, then generate mediants InitialState = {queue:from_list([{0, 1}, {1, 1}]), {0, 1}, {1, 0}}, @@ -320,15 +343,15 @@ make_sb_gen({Queue, {LA, LB}, {RA, RB}}) -> %%% Constrained Generators (Public API) %%% ============================================================================ -%% @doc Create a constrained naturals generator. --spec constrained_naturals(non_neg_integer(), non_neg_integer()) -> generator_fun(). -constrained_naturals(Min, Max) -> - naturals(#{value => {range, Min, Max}}). +%% @doc Create a constrained natural generator. +-spec constrained_natural(non_neg_integer(), non_neg_integer()) -> generator_fun(). +constrained_natural(Min, Max) -> + natural(#{value => {range, Min, Max}}). -%% @doc Create a constrained integers generator. --spec constrained_integers(integer(), integer()) -> generator_fun(). -constrained_integers(Min, Max) -> - integers(#{value => {range, Min, Max}}). +%% @doc Create a constrained integer generator. +-spec constrained_integer(integer(), integer()) -> generator_fun(). +constrained_integer(Min, Max) -> + integer(#{value => {range, Min, Max}}). %%% ============================================================================ %%% Function Relations |