diff --git a/args.c b/args.c
index ec2a2fa..56779b8 100644
--- a/args.c
+++ b/args.c
@@ -6,6 +6,8 @@
 
 #include "args.h"
 
+#include "comp_features.h"
+
 #define _PASTE_(x, y) x ## y
 #define _PASTE(x, y) _PASTE_(x, y)
 
@@ -19,6 +21,115 @@
 			_box_name(pT); })
 
 typedef __typeof( *((pargs_t*)0)->fd_pass ) fd_pass_t;
+typedef __typeof( ((pargs_t*)0)->replace ) replace_t;
+
+struct input_arguments
+{
+	int *restrict p_argc;
+	char** *restrict p_argv;
+	char** *restrict p_envp;
+};
+
+typedef bool (single_arg_parse_func)(int, const char*, struct input_arguments* restrict, pargs_t*);
+typedef void (single_arg_error_func)(struct arg_parse_error* restrict);
+
+enum argument_type {
+	AT_SHORT = 0,
+	AT_LONG,
+	AT_LONG_EQ,
+
+	AT_LONG_OR_EQ = AT_LONG | AT_LONG_EQ,
+};
+
+struct argument_parser {
+	union {
+		const char* l;
+		char s;
+	} name;
+
+	enum argument_type kind;
+
+	bool is_default;
+
+	const char* destription;
+	const char* example;
+
+	single_arg_parse_func* parse;
+	single_arg_error_func* error;
+};
+
+typedef __typeof( ((struct argument_parser*)0)->name ) av_name_t;
+
+static bool _si_handle_replace(int idx, const char* arg, struct input_arguments* restrict in, pargs_t* out)
+{
+	char c;
+	bool* restrict repl;
+	switch(c = *arg) {
+		case 'i':
+		case 'I': 
+			repl = &out->replace.in;
+			break;
+		case 'o': 
+		case 'O':
+			repl = &out->replace.out;
+			break;
+		case 'e': 
+		case 'E': 
+			repl = &out->replace.err;
+			break;
+		default: return false;
+	}
+	*repl = !(c & 0x20);
+	return true;
+}
+
+static const struct argument_parser AV_ARGS[] = {
+	{ { .s= 'i' }, AT_SHORT, true, "Sink stdin", NULL, _si_handle_replace, NULL },
+	{ { .s='o' }, AT_SHORT, true, "Sink stdout", NULL, _si_handle_replace, NULL },
+	{ { .s='e' }, AT_SHORT, false, "Sink stderr", NULL, _si_handle_replace, NULL },
+
+	{ { .s='I' }, AT_SHORT, false, "Keep stdin", NULL, _si_handle_replace, NULL },
+	{ { .s='O' }, AT_SHORT, false, "Keep stdout", NULL, _si_handle_replace, NULL },
+	{ { .s='E' }, AT_SHORT, true, "Keep stderr", NULL, _si_handle_replace, NULL },
+};
+#define AV_ARGS_SZ (sizeof(AV_ARGS) / sizeof(struct argument_parser))
+
+static inline bool _av_long_extract_name(const char* name, enum argument_type ty, view_t* restrict out)
+{
+	register bool ok = true;
+	switch(ty) {
+		case AT_LONG_EQ:
+			ok = !!sv_split_cstr(name, '=', out, NULL);
+			break;
+		case AT_LONG_OR_EQ:
+			if(!sv_split_cstr(name, '=', out, NULL)) {
+				if(0)
+		case AT_SHORT:	name = (const char[2]){*name, 0};
+				*out = sv_from_cstr(name);
+			}
+			break;
+		default: return false;
+	}
+	return ok;
+}
+
+static inline const struct argument_parser* _av_lookup(av_name_t name, enum argument_type ty)
+{
+	for(size_t i=0;i<AV_ARGS_SZ;i++) {
+		const struct argument_parser* current = AV_ARGS+i;
+		if(__builtin_constant_p(ty) && ty == AT_SHORT) {
+			if(current->name.s == name.s) return current;
+		} else switch(ty) {
+			case AT_SHORT: if(current->name.s == name.s) return current;
+			default: {
+				view_t real_name;
+				if(!_av_long_extract_name(name.l, ty, &real_name)) continue; // Argument requires `=` but one wasn't fount, continue.
+				if(sv_eq_cstr(real_name, current->name.l)) return current;
+			} break;
+		}
+	}
+	return NULL;
+}
 
 const pargs_t* parsed_args = NULL;
 static const pargs_t default_args[1] = { A_DEFAULT_ARGS }; //A_DEFAULT_ARGS_P;
@@ -143,11 +254,65 @@ const pargs_t* a_get_program_args() {
 
 bool a_is_parsed() { return parsed_args != NULL; }
 
-bool a_parse_into(union arg_parse_result *restrict parsed, int *restrict argc, char** *restrict p_argv, char** *restrict p_envp)
+static bool a_parse__short(int i, const char* arg, struct input_arguments in, pargs_t* restrict out)
+{
+	const struct argument_parser* p = _av_lookup( (av_name_t){ .s = *arg, }, AT_SHORT );
+	if(!p) return false;
+	else {
+		if(!p->parse(i, arg, &in, out)) {
+			if(p->error) {
+				//TODO: How to handle returning `struct arg_parse_error`? Make `out` union arg_parse_result* restrict` instead?
+			}
+			return false;
+		}
+	}
+	return true;
+}
+
+static bool a_parse__long(int i, const char* arg, struct input_arguments in, pargs_t* restrict out)
 {
-	//TODO
-	parsed->err = (struct arg_parse_error) { .kind = A_PF_UNKNOWN, ._data = { .none = {} } };
-	return false;
+	//TODO: determine if `arg` is `k=v` or not
+	bool is_eq = /* TODO */ false;
+	const struct argument_parser* p = _av_lookup( (av_name_t){ .l = arg, }, is_eq ? AT_LONG_EQ : AT_LONG );
+	if(!p) return false;
+	else {
+		//TODO :if(!p->parse(
+	}
+
+	return true;
+}
+
+inline static bool _a_parse_into(union arg_parse_result *restrict parsed, struct input_arguments input)
+{
+	bool ok = true;;
+	pargs_t args = A_DEFAULT_ARGS;
+	
+	//TODO: Parse arguments
+
+_end:
+	if(ok)
+_set_ok:	parsed->ok = args;
+	else 
+_set_err:	parsed->err = (struct arg_parse_error) { .kind = A_PF_UNKNOWN, ._data = { .none = {} } };
+
+	return ok;
+}
+
+
+inline bool a_parse_into(union arg_parse_result *restrict parsed, int *restrict p_argc, char** *restrict p_argv, char** *restrict p_envp)
+{
+#if FEATURE_HAS_FLAG(NO_ARGS)
+	parsed->ok = A_DEFAULT_ARGS;
+	return true;
+#else
+	struct input_arguments input = {
+		p_argc,
+		p_argv,
+		p_envp,
+	};
+
+	return _a_parse_into(parsed, input);
+#endif
 }
 
 const struct arg_parse_error* a_parse(int *restrict argc, char** *restrict p_argv, char** *restrict p_envp)
diff --git a/view.c b/view.c
index 2d7fac3..0aa73a4 100644
--- a/view.c
+++ b/view.c
@@ -12,6 +12,20 @@
 #define $nullchk(ptr, or) ({ __auto_type _$p = (ptr); \
 			__builtin_expect(_$p == NULL, false) ? ({ or; }),NULL : _$p; })
 
+#define min(x, y) ({	__auto_type _$min_x = (x); \
+			__auto_type _$min_y = (y); \
+			_$min_x < _$min_y ? _$min_x : _$min_y; })
+
+#define ptrdiff(x, y) ({ \
+			__auto_type _$ptrdiff_x = (x); \
+			__auto_type _$ptrdiff_y = (y); \
+			(ptrdiff_t)((_$ptrdiff_x < _$ptrdiff_y) \
+					? ((uintptr_t)_$ptrdiff_y) - ((uintptr_t)_$ptrdiff_x) \
+					: ((uintptr_t)_$ptrdiff_x) - ((uintptr_t)_$ptrdiff_y)); \
+			})
+
+
+
 typedef uint8_t byte_t;
 
 __attribute__((packed))
@@ -111,3 +125,94 @@ size_t sv_copy_to(size_t sz, char buffer[restrict static sz], view_t view)
 		return _sv_copy_manual(sz, buffer, view);
 	}
 }
+
+// String views //
+
+inline view_t sv_from_cstr(const char* p)
+{
+	return (view_t) {
+		.len = strlen(p),
+		.ptr = (char*)p,
+	};
+}
+
+inline view_t sv_slice_cstr(const char* p, size_t n)
+{
+	if(__builtin_constant_p(n) && !n ) return (view_t) { .len = 0, .ptr = (char*)p };
+	else return (view_t) { .len = min(strlen(p), n), .ptr = (char*)p };
+}
+
+inline view_t sv_slice(view_t v, size_t s, size_t n)
+{
+	if(__builtin_expect((s = min(v.len, s)) == v.len,false)) return (view_t) { .len = 0, .ptr = v.ptr+v.len };
+	else {
+		return (view_t) {
+			.len = n 
+				? min(v.len - s, n)//min(v.len,n) - s 
+				: v.len - s, //XXX: Test this, I think it's correct, but dunno...
+			.ptr = v.ptr + s,
+		};
+	}
+}
+
+inline size_t sv_split(view_t p, char on, view_t* restrict first, view_t* restrict second)
+{
+	if(__builtin_constant_p(first) && __builtin_constant_p(second) && !first && !second) 
+		return (size_t)(((uintptr_t) $nullchk(memchr(p.ptr, (int)on, p.len), return 0)) - (uintptr_t)p.ptr);
+	else {
+		char* start = memchr(p.ptr, (int)on, p.len); // `on` chr here
+		if(__builtin_expect(start==NULL, false)) return 0;
+
+		size_t diff = (size_t)ptrdiff(p.ptr, start);
+		if(first) *first = (view_t) {
+			.len = diff,
+			.ptr = p.ptr,
+		};
+		if(second) *second = (view_t) {
+			.len = (p.len - diff) + 1, //XXX: WARNING: this might be an off-by-1 error...
+			.ptr = start + 1,
+		};
+		
+		return diff;
+	}
+}
+
+size_t sv_split_cstr(const char* p, char on, view_t* restrict first, view_t* restrict second)
+{
+	return sv_split(sv_from_cstr(p), on, first, second);
+}
+
+inline char* sv_to_cstr(view_t view, char* restrict buffer, size_t n)
+{
+	if(__builtin_constant_p(buffer) && !buffer) {
+		if(__builtin_constant_p(n) && !n) return strndup(view.ptr, view.len);
+		else return strndup(view.ptr, n ? min(n, view.len) : view.len);
+	} else {
+		if(__builtin_constant_p(n) && !n) {
+			return buffer;
+		} else {
+			sv_copy_to(n, buffer, view);
+			return buffer;
+		}
+	}
+}
+
+__attribute__((malloc))
+char* sv_dupto_cstr(view_t view)
+{
+	return sv_to_cstr(view, NULL, 0);
+}
+
+bool sv_eq_cstr(view_t a, const char* b)
+{
+	return strncmp(a.ptr, b, a.len) == 0 && strlen(b) == a.len;
+}
+
+bool sv_eq(view_t a, view_t b)
+{
+	return a.len == b.len && (__builtin_expect(a.ptr == b.ptr, false) || memcmp(a.ptr, b.ptr, a.len));
+}
+
+
+
+
diff --git a/view.h b/view.h
index 379e5c1..3864441 100644
--- a/view.h
+++ b/view.h
@@ -3,6 +3,7 @@
 
 #include <stdint.h>
 #include <stddef.h>
+#include <stdbool.h>
 
 typedef struct string_view {
 	size_t len;
@@ -19,7 +20,31 @@ struct string;
 view_t s_get_str(str_info_t data) __attribute__((pure));
 str_info_t s_get_info(view_t str) __attribute__((pure));
 
+view_t sv_slice(view_t v, size_t s, size_t n);
+size_t sv_split(view_t p, char on, view_t* restrict first, view_t* restrict second);
+
+view_t sv_from_cstr(const char* p);
+view_t sv_slice_cstr(const char* p, size_t n);
+
+__attribute__((__gnu_inline__))
+extern inline size_t sv_split_cstr(const char* p, char on, view_t* restrict first, view_t* restrict second)
+{
+	return sv_split(sv_from_cstr(p), on, first, second);
+}
+
 /// Copy `view` into nul-terminated `buffer`, up to `size` bytes. Return the number of bytes that would've been copied regardless of `sz` (incl. nul-terminator)
 size_t sv_copy_to(size_t sz, char buffer[restrict static sz], view_t view);
+char* sv_to_cstr(view_t view, char* restrict buffer, size_t n);
+
+__attribute__((__gnu_inline__, malloc))
+extern inline char* sv_dupto_cstr(view_t view) 
+{ return sv_to_cstr(view, (char*)0, 0); }
+
+bool sv_eq_cstr(view_t a, const char* b);
+__attribute__((__gnu_inline__))
+extern inline bool sv_eq(view_t a, view_t b)
+{
+	return a.len == b.len && (__builtin_expect(a.ptr == b.ptr, false) || (&sv_eq)(a, b));
+}
 
 #endif /* _VIEW_H */