b/c...py: skip_first: support fractional seconds

bytebeat_compiler.py

@@ -54,6 +54,18 @@ DEFAULT_PARAMETERS = {
 
 stdout_atty = hasattr(stdout, "isatty") and stdout.isatty()
 
+def is_decimal_number(s:  str) -> bool:
+    if s.count('.') > 1:  # More than one decimal point
+        return False
+
+    if s.startswith(('+', '-')):
+        s = s[1:]  # Remove the sign for further checks
+
+    if s.replace('.', '', 1).isdigit():
+        return True
+
+    return False
+
 def fetch(name: str):
 	if from_env := environ.get(name):
 		return from_env
@@ -328,17 +340,22 @@ if __name__ == "__main__":
 
 	# - Parse the '--skip-first' argument
 	if not args.skip_first is None:
+		encountered_point = False
 		encountered_s = False
 		for character in args.skip_first:
-			if character.isdigit() or character == "s" and not encountered_s:
-				if character == "s":
+			if character.isdigit() or character == "." and \
+			   not encountered_point or character == "s" and not encountered_s:
+				if character == ".":
+					encountered_point = True
+				elif character == "s":
 					encountered_s = True
 			else:
-				print(f"Invalid --skip-first format: `{args.skip_first}`")
-				exit(1)
+				raise SystemExit( "Invalid --skip-first format: "
+				                 f"`{args.skip_first}`")
 
 		skip_first = \
-			[int(x) if x.isdigit() else 0 for x in args.skip_first.split("s")]
+			[Decimal(x) if is_decimal_number(x) else 0 for x in \
+			 args.skip_first.split("s")]
 
 		skip_first_samples = 0
 		if len(skip_first) == 1:
@@ -348,6 +365,9 @@ if __name__ == "__main__":
 	else:
 		skip_first_samples = 0
 
+	# round the number of skipped first samples
+	skip_first_samples = ceil(skip_first_samples)
+
 	length_formula = lambda channels, samples, n: channels * (samples + n)
 	gen_length = length_formula(args.channels, samples, 0)
 	loop_end = length_formula(args.channels, samples, skip_first_samples)