From 7d8ba6fc28487901a6f73d75eb59dabe416fe391 Mon Sep 17 00:00:00 2001
From: VegOwOtenks <vegowotenks@jossco.de>
Date: Tue, 1 Oct 2024 11:06:04 +0200
Subject: [PATCH] More functional-style stringview functions

---
 src/StringView/StringView.c | 28 ++++++++++++++++++++++++++++
 src/StringView/StringView.h |  8 ++++++++
 2 files changed, 36 insertions(+)

diff --git a/src/StringView/StringView.c b/src/StringView/StringView.c
index 95f2e88..aace3d5 100644
--- a/src/StringView/StringView.c
+++ b/src/StringView/StringView.c
@@ -119,6 +119,24 @@ StringView StringView_FindString(StringView haystack, StringView needle)
 	return (StringView) {NULL, 0};
 }
 
+StringView StringView_Drop(StringView string, size_t length)
+{
+	return StringView_Slice(string, length, string.length);
+}
+
+StringView StringView_TakeWhile(StringView string, StringViewContinue function)
+{
+	size_t length = 0;
+	for (length = 0; string.length != length && function(string.source[length]); length++);
+
+	return StringView_Take(string, length);
+}
+
+StringView StringView_Take(StringView string, size_t length)
+{
+	return StringView_Slice(string, 0, length);
+}
+
 StringView StringView_Slice(StringView string, size_t start, size_t end)
 {
 	if (end > string.length || start > string.length) {
@@ -200,6 +218,16 @@ StringView StringView_StripRight(StringView sv, StringView strip)
 	return sv;
 }
 
+void* StringView_FoldLeft(StringView string, void* initial, StringViewFoldFunction function)
+{
+	void* value = initial;
+	while (string.length != 0) {
+		value = function(string.source[0], value);
+		string = StringView_Drop(string, 1);
+	}
+
+	return value;
+}
 
 void StringView_Paste(char* destination, StringView source)
 {
diff --git a/src/StringView/StringView.h b/src/StringView/StringView.h
index 3c57de9..98e1f79 100644
--- a/src/StringView/StringView.h
+++ b/src/StringView/StringView.h
@@ -44,7 +44,12 @@ size_t StringView_Count(StringView string, StringView find);
 
 size_t StringView_FindStringOffset(StringView haystack, StringView needle);
 StringView StringView_FindString(StringView haystack, StringView needle);
+
+typedef bool (*StringViewContinue) (char);
 StringView StringView_Slice(StringView string, size_t start, size_t end); // start and end are offsets
+StringView StringView_Drop(StringView string, size_t length);
+StringView StringView_Take(StringView string, size_t length);
+StringView StringView_TakeWhile(StringView string, StringViewContinue function);
 
 bool StringView_Partition(StringView* left, StringView* right, StringView source, StringView delim);
 bool StringView_NextSplit(StringView* dest, StringView* source, StringView delim);
@@ -53,6 +58,9 @@ bool StringView_LastSplit(StringView* dest, StringView* source, StringView delim
 StringView StringView_StripLeft(StringView sv, StringView strip);
 StringView StringView_StripRight(StringView sv, StringView strip);
 
+typedef void* (*StringViewFoldFunction) (char, void*);
+void* StringView_FoldLeft(StringView string, void* initial, StringViewFoldFunction function);
+
 void StringView_Paste(char* destination, StringView source);
 
 int StringView_ParseInt(StringView source);