Introduce the tab_width setting and give tabs a greater value when counting indentation level.

src/parser/util.rs

@@ -20,6 +20,7 @@ use crate::context::RefContext;
 use crate::error::CustomError;
 use crate::error::MyError;
 use crate::error::Res;
+use crate::types::IndentationLevel;
 
 pub(crate) const WORD_CONSTITUENT_CHARACTERS: &str =
     "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
@@ -240,7 +241,7 @@ pub(crate) fn org_space<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, char> {
 pub(crate) fn org_space_or_line_ending<'s>(
     input: OrgSource<'s>,
 ) -> Res<OrgSource<'s>, OrgSource<'s>> {
-    alt((recognize(one_of(" \t")), org_line_ending))(input)
+    alt((recognize(org_space), org_line_ending))(input)
 }
 
 /// Match a line break or the end of the file.
@@ -249,3 +250,20 @@ pub(crate) fn org_space_or_line_ending<'s>(
 pub(crate) fn org_line_ending<'s>(input: OrgSource<'s>) -> Res<OrgSource<'s>, OrgSource<'s>> {
     alt((line_ending, eof))(input)
 }
+
+/// Match the whitespace at the beginning of a line and give it an indentation level.
+pub(crate) fn indentation_level<'b, 'g, 'r, 's>(
+    context: RefContext<'b, 'g, 'r, 's>,
+    input: OrgSource<'s>,
+) -> Res<OrgSource<'s>, (IndentationLevel, OrgSource<'s>)> {
+    let (remaining, leading_whitespace) = space0(input)?;
+    let indentation_level = Into::<&str>::into(leading_whitespace)
+        .chars()
+        .map(|c| match c {
+            ' ' => 1,
+            '\t' => context.get_global_settings().tab_width,
+            _ => unreachable!(),
+        })
+        .sum();
+    Ok((remaining, (indentation_level, leading_whitespace)))
+}