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authorBen Culkin <scorpress@gmail.com>2020-12-03 19:28:15 -0500
committerBen Culkin <scorpress@gmail.com>2020-12-03 19:28:15 -0500
commitf3814a84f8471684cd483347db4fb7b107c2e635 (patch)
tree7ed1061ee69ef50cd1494cfacc866b271b8d1163 /base/src/main/java/bjc/utils/patterns/PatternMatcher.java
parenta2c7425458f645802a352abc4783e0afc73dba13 (diff)
Rename interfaces to match Java style
Rename several interfaces that were in the style IWhatever, which Java doesn't use
Diffstat (limited to 'base/src/main/java/bjc/utils/patterns/PatternMatcher.java')
-rw-r--r--base/src/main/java/bjc/utils/patterns/PatternMatcher.java96
1 files changed, 70 insertions, 26 deletions
diff --git a/base/src/main/java/bjc/utils/patterns/PatternMatcher.java b/base/src/main/java/bjc/utils/patterns/PatternMatcher.java
index f144d36..40bf42b 100644
--- a/base/src/main/java/bjc/utils/patterns/PatternMatcher.java
+++ b/base/src/main/java/bjc/utils/patterns/PatternMatcher.java
@@ -1,41 +1,85 @@
package bjc.utils.patterns;
-import bjc.data.*;
+import java.util.function.*;
+
+import bjc.functypes.*;
/**
- * Implements pattern-matching (of a sort) against a collection of patterns.
+ * Represents a pattern matcher against a series of patterns.
*
* @author Ben Culkin
- *
- * @param <ReturnType> The type returned by the pattern.
+ *
+ * @param <ReturnType> The type returned from matching the patterns.
+ * @param <InputType> The type to match against.
*/
-public class PatternMatcher<ReturnType, InputType>
- implements IPatternMatcher<ReturnType, InputType> {
- private final ComplexPattern<ReturnType, Object, InputType>[] patterns;
+@FunctionalInterface
+public interface PatternMatcher<ReturnType, InputType> {
+ /**
+ * Match an input object against a set of patterns.
+ *
+ * @param input The object to match against.
+ *
+ * @return The result of matching against the object.
+ *
+ * @throws NonExhaustiveMatch If none of the patterns in this set match
+ */
+ ReturnType matchFor(InputType input) throws NonExhaustiveMatch;
/**
- * Create a new pattern matcher.
+ * Create a pattern matcher against a static set of patterns.
*
- * @param patterns The set of patterns to match against.
+ * @param <RetType> The type returned from matching the patterns.
+ * @param <InpType> The type to match against.
+ *
+ * @param patterns The set of patterns to match on.
+ *
+ * @return A pattern matcher which matches on the given patterns.
*/
- @SuppressWarnings("unchecked")
@SafeVarargs
- public PatternMatcher(ComplexPattern<ReturnType, ?, InputType>...patterns) {
- // Note: this may seem a somewhat questionable cast, but because we never
- // actually do anything with the value who has a type matching the second
- // parameter, this should be safe
- this.patterns = (ComplexPattern<ReturnType, Object, InputType>[]) patterns;
+ static <RetType, InpType> PatternMatcher<RetType, InpType> matchingOn(
+ ComplexPattern<RetType, ?, InpType>... patterns) {
+ return new SimplePatternMatcher<>(patterns);
+ }
+
+ /**
+ * Create a pattern matcher from a handler function.
+ *
+ * @param <RetType> The type returned by the matcher.
+ * @param <InpType> The type to match against.
+ *
+ * @param handler The handler function.
+ *
+ * @return A pattern matcher defined by the given handler.
+ */
+ static <RetType, InpType> PatternMatcher<RetType, InpType> from(
+ ThrowFunction<InpType, RetType, NonExhaustiveMatch> handler) {
+ return new FunctionalPatternMatcher<>(handler);
+ }
+
+ /**
+ * Create a pattern matcher which applies a transform to its input.
+ *
+ * @param <NewInput> The new input type to use.
+ * @param transformer The function to convert from the new input to the old input.
+ *
+ * @return A pattern matcher which takes values of the new type instead.
+ */
+ default <NewInput> PatternMatcher<ReturnType, NewInput> transformInput(
+ Function<NewInput, InputType> transformer) {
+ return from(inp -> matchFor(transformer.apply(inp)));
}
- @Override
- public ReturnType matchFor(InputType input) throws NonExhaustiveMatch {
- for (ComplexPattern<ReturnType, Object, InputType> pattern : patterns) {
- Pair<Boolean, Object> matches = pattern.matches(input);
- if (matches.getLeft()) {
- pattern.apply(input, matches.getRight());
- }
- }
-
- throw new NonExhaustiveMatch("Non-exhaustive match against " + input);
+ /**
+ * Create a pattern matcher which applies a transform to its output.
+ *
+ * @param <NewOutput> The new output type to use.
+ *
+ * @param transformer The function to convert from the new output to the old output.
+ *
+ * @return A pattern matcher which takes values of the new type instead.
+ */
+ default <NewOutput> PatternMatcher<NewOutput, InputType> transformOutput(
+ Function<ReturnType, NewOutput> transformer) {
+ return from(inp -> transformer.apply(matchFor(inp)));
}
-}
+} \ No newline at end of file