vet: simplify fn name identifying, add warning for incomplete documentation (#8227)

cmd/tools/vvet/tests/module_file_test.out

@@ -2,3 +2,4 @@ cmd/tools/vvet/tests/module_file_test.vv:7: warning: Function documentation seem
 cmd/tools/vvet/tests/module_file_test.vv:13: warning: A function name is missing from the documentation of "pub fn bar() string".
 cmd/tools/vvet/tests/module_file_test.vv:35: warning: Function documentation seems to be missing for "pub fn (f Foo) foo() string".
 cmd/tools/vvet/tests/module_file_test.vv:46: warning: A function name is missing from the documentation of "pub fn (f Foo) fooo() string".
+cmd/tools/vvet/tests/module_file_test.vv:52: warning: The documentation for "pub fn (f Foo) boo() string" seems incomplete.

cmd/tools/vvet/tests/module_file_test.vv

@@ -47,3 +47,9 @@ pub fn (f Foo) fooo() string {
 	// not using convention
 	return f.fo()
 }
+
+// boo
+pub fn (f Foo) boo() string {
+	// Incomplete doc
+	return f.fo()
+}

cmd/tools/vvet/vvet.v

@@ -172,30 +172,22 @@ fn (mut vet Vet) vet_line(lines []string, line string, lnumber int) {
 			}
 			ident_fn_name := fn (line string) string {
 				mut fn_idx := line.index(' fn ') or { return '' }
-				mut skip := false
-				mut p_count := 0
-				mut fn_name := ''
-				for i := fn_idx + 4; i < line.len; i++ {
-					char := line[i]
-					if !skip && char == `(` {
-						p_count++
-						skip = true
-						continue
-					} else if skip && char == `)` {
-						skip = false
-						continue
-					} else if char == ` ` {
-						continue
-					} else if char.is_letter() {
-						// fn_name += char.str()
-						fn_name = line[i..].all_before('(')
-						break
-					}
-					if p_count > 1 {
-						break
+				if line.len < fn_idx + 5 {
+					return ''
+				}
+				mut tokens := line[fn_idx + 4..].split(' ')
+				// Skip struct identifier
+				if tokens.first().starts_with('(') {
+					fn_idx = line.index(')') or { return '' }
+					tokens = line[fn_idx..].split(' ')
+					if tokens.len > 1 {
+						tokens = [tokens[1]]
 					}
 				}
-				return fn_name
+				if tokens.len > 0 {
+					return tokens[0].all_before('(')
+				}
+				return ''
 			}
 			mut line_above := lines[lnumber - 1]
 			mut tags := []string{}
@@ -230,6 +222,14 @@ fn (mut vet Vet) vet_line(lines []string, line string, lnumber int) {
 					} else if prev_line.starts_with('// $fn_name ') {
 						grab = false
 						break
+					} else if prev_line.starts_with('// $fn_name') {
+						grab = false
+						if is_pub_fn {
+							clean_line := line.all_before_last('{').trim(' ')
+							vet.warn('The documentation for "$clean_line" seems incomplete.',
+								lnumber, .doc)
+						}
+						break
 					} else if prev_line.starts_with('[') {
 						tags << collect_tags(prev_line)
 						continue