Initial commit

7 files changed, 278 insertions, 1 deletions

diff --git a/.clang-format b/.clang-format
new file mode 100644
index 0000000..b360796
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,90 @@
+---
+Language:        Cpp
+# BasedOnStyle:  Chromium
+AccessModifierOffset: -1
+AlignAfterOpenBracket: Align
+AlignConsecutiveAssignments: false
+AlignConsecutiveDeclarations: false
+AlignEscapedNewlinesLeft: true
+AlignOperands:   true
+AlignTrailingComments: true
+AllowAllParametersOfDeclarationOnNextLine: false
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: Inline
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: None
+AlwaysBreakAfterReturnType: None
+AlwaysBreakBeforeMultilineStrings: true
+AlwaysBreakTemplateDeclarations: true
+BinPackArguments: true
+BinPackParameters: false
+BraceWrapping:   
+  AfterClass:      false
+  AfterControlStatement: false
+  AfterEnum:       false
+  AfterFunction:   false
+  AfterNamespace:  false
+  AfterObjCDeclaration: false
+  AfterStruct:     false
+  AfterUnion:      false
+  BeforeCatch:     false
+  BeforeElse:      false
+  IndentBraces:    false
+BreakBeforeBinaryOperators: None
+BreakBeforeBraces: Attach
+BreakBeforeTernaryOperators: true
+BreakConstructorInitializersBeforeComma: false
+ColumnLimit:     80
+CommentPragmas:  '^ IWYU pragma:'
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
+ConstructorInitializerIndentWidth: 4
+ContinuationIndentWidth: 4
+Cpp11BracedListStyle: true
+DerivePointerAlignment: false
+DisableFormat:   false
+ExperimentalAutoDetectBinPacking: false
+ForEachMacros:   [ foreach, Q_FOREACH, BOOST_FOREACH ]
+IncludeCategories: 
+  - Regex:           '^<.*\.h>'
+    Priority:        1
+  - Regex:           '^<.*'
+    Priority:        2
+  - Regex:           '.*'
+    Priority:        3
+IndentCaseLabels: true
+IndentWidth:     2
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: false
+MacroBlockBegin: ''
+MacroBlockEnd:   ''
+MaxEmptyLinesToKeep: 1
+NamespaceIndentation: None
+ObjCBlockIndentWidth: 2
+ObjCSpaceAfterProperty: false
+ObjCSpaceBeforeProtocolList: false
+PenaltyBreakBeforeFirstCallParameter: 1
+PenaltyBreakComment: 300
+PenaltyBreakFirstLessLess: 120
+PenaltyBreakString: 1000
+PenaltyExcessCharacter: 1000000
+PenaltyReturnTypeOnItsOwnLine: 200
+PointerAlignment: Left
+ReflowComments:  true
+SortIncludes:    false
+SpaceAfterCStyleCast: false
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpaceInEmptyParentheses: false
+SpacesBeforeTrailingComments: 2
+SpacesInAngles:  false
+SpacesInContainerLiterals: true
+SpacesInCStyleCastParentheses: false
+SpacesInParentheses: false
+SpacesInSquareBrackets: false
+Standard:        Auto
+TabWidth:        8
+UseTab:          Never
+...
+
diff --git a/.gitignore b/.gitignore
index b8d81fd..7efa141 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
-.o
+*.o
+*.dSYM
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..bab241f
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,9 @@
+CC = gcc
+CFLAGS = -Wall -g
+
+example: example.c functional.c
+	$(CC) $(CFLAGS) -o example.o example.c functional.c && ./example.o
+
+.PHONY: format
+format:
+	clang-format -i -style=file *.{c,h}
diff --git a/example.c b/example.c
new file mode 100644
index 0000000..f5d44b5
--- /dev/null
+++ b/example.c
@@ -0,0 +1,95 @@
+#include "functional.h"
+#define MAX_STR_SIZE 400
+
+typedef struct {
+  unsigned int age;
+  char* name;
+} Person;
+
+bool shouldIncludePerson(FunctionalArgs* args) {
+  const char* toExclude = args->ctxp;
+  Person* first = args->arr;
+  Person* p = &first[args->i];
+  return p->age > 30 && strcmp(toExclude, p->name);
+}
+
+void* derefPerson(int i, void* arr) {
+  Person* p = arr;
+  return (void*)&p[i];
+}
+
+int stringifyPerson(Person* p, char* out, size_t n) {
+  return snprintf(out, n, "Person %s is %d years of age, yo\n", p->name,
+                  p->age);
+}
+
+void printPerson(Person* p) {
+  char personStr[MAX_STR_SIZE];
+  stringifyPerson(p, personStr, MAX_STR_SIZE);
+  printf("%s", personStr);
+}
+
+void shiftPersonLeft(FunctionalArgs* args) {
+  Person* people = args->arr;
+  for (int i = args->i; i < args->n - 1; i++) {
+    people[i] = people[i + 1];
+  }
+  args->n--;
+}
+
+void mapPersonToAge(FunctionalArgs* args) {
+  int* storage = args->storage;
+  Person* people = args->arr;
+  storage[args->i] = people[args->i].age;
+}
+
+void copyPerson(FunctionalArgs* args) {
+  Person* src = args->arr;
+  Person* dest = args->storage;
+  dest[args->i - args->offset] = src[args->i];
+}
+
+void mapExample(Functional* f) {
+  func_map(f);
+  for (int i = 0; i < f->args.n; i++) {
+    int* ages = f->args.storage;
+    printf("age[%d] = %d\n", i, ages[i]);
+  }
+}
+
+void filterExample(Functional* f) {
+  func_filter(f);
+  for (int i = 0; i < f->args.n; i++) {
+    Person* people = f->args.storage;
+    printPerson(&people[i]);
+  }
+}
+
+void findExample(Functional* f) {
+  Person* olderAndNotHarry = func_find(f);
+  printPerson(olderAndNotHarry);
+}
+
+int main() {
+  Person people[] = {{.age = 19, .name = "Alex"},
+                     {.age = 42, .name = "Jenna"},
+                     {.age = 55, .name = "Tom"}};
+  int ages[3];
+  Person filteredPeople[3];
+  Functional func = {
+      .args = {.i = 0,
+               .n = 3,
+               .arr = (void*)people,
+               .ctxp = (void*)"Harry",
+               .storage = filteredPeople},
+      .filter = shouldIncludePerson,
+      .map = copyPerson,
+      .derefInput = derefPerson,
+  };
+  findExample(&func);
+  filterExample(&func);
+  func.args.storage = ages;
+  func.map = mapPersonToAge;
+  func.args.n = 3;
+  mapExample(&func);
+}
diff --git a/functional.c b/functional.c
new file mode 100644
index 0000000..c1577bd
--- /dev/null
+++ b/functional.c
@@ -0,0 +1,50 @@
+#include "functional.h"
+
+void func_map(Functional* f) {
+  f->args.i = 0;
+  f->args.offset = 0;
+  while (f->args.i < f->args.n) {
+    f->map(&f->args);
+    f->args.i++;
+  }
+}
+
+void func_filterGeneric(Functional* f,
+                        void (*shiftLeft)(FunctionalArgs* args)) {
+  bool shouldMutate = shiftLeft != NULL;
+  int nInCollection = 0;
+  for (f->args.i = 0; f->args.i < f->args.n; f->args.i++) {
+    bool shouldInclude = f->filter(&f->args);
+    if (shouldInclude) {
+      f->args.offset = f->args.i - nInCollection;
+      if (!shouldMutate) {
+        f->map(&f->args);
+      }
+      nInCollection++;
+    } else {
+      if (shouldMutate) {
+        shiftLeft(&f->args);
+      }
+    }
+  }
+  f->args.n = nInCollection;
+}
+
+void func_filter(Functional* f) {
+  func_filterGeneric(f, NULL);
+}
+
+void func_filterMutate(Functional* f, void (*shiftLeft)(FunctionalArgs* args)) {
+  func_filterGeneric(f, shiftLeft);
+}
+
+void* func_find(Functional* f) {
+  f->args.i = 0;
+  while (f->args.i < f->args.n) {
+    if (f->filter(&f->args)) {
+      return f->derefInput(f->args.i, f->args.arr);
+    }
+    f->args.i++;
+  }
+  return NULL;
+}
diff --git a/functional.h b/functional.h
new file mode 100644
index 0000000..fe7a869
--- /dev/null
+++ b/functional.h
@@ -0,0 +1,32 @@
+#ifndef FUNCTIONAL_H
+#define FUNCTIONAL_H
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+  int i;
+  int offset;
+  int n;
+  void* arr;
+  void* ctxp;
+  void* storage;
+} FunctionalArgs;
+
+typedef struct {
+  bool (*filter)(FunctionalArgs* args);
+  void (*map)(FunctionalArgs* args);
+  void* (*derefInput)(int i, void* j);  // callback used to deference arr[i]
+  void (*shiftLeft)(FunctionalArgs* f);
+  FunctionalArgs args;
+} Functional;
+
+void func_map(Functional* f);
+
+void func_filter(Functional* f);
+
+void* func_find(Functional* f);
+
+#endif
diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/readme.md