Grcov report - forms.rs

1

//! Reader macros for quote / quasiquote / unquote / unquote-splicing

2

//! plus the parenthesised list parser (including the dotted-pair tail

3

//! `(a . b)` form).

4

5

use winnow::combinator::cut_err;

6

use winnow::error::{AddContext, ContextError, ErrMode, ModalResult, StrContext, StrContextValue};

7

use winnow::prelude::*;

8

9

use crate::ast::Expr;

10

11

use super::parse_expr;

12

use super::whitespace::skip_ws_and_comments_no_annotations;

13

14

5722298

pub(super) fn parse_quote(input: &mut &str) -> ModalResult<Expr> {

15

5722298

    let _ = '\''.parse_next(input)?;

16

43799

    let expr = parse_expr.parse_next(input)?;

17

43799

    Ok(Expr::Quote(Box::new(expr)))

18

5722298

19

20

5678499

pub(super) fn parse_quasiquote(input: &mut &str) -> ModalResult<Expr> {

21

5678499

    let _ = '`'.parse_next(input)?;

22

1363

    let expr = parse_expr.parse_next(input)?;

23

1363

    Ok(Expr::Quasiquote(Box::new(expr)))

24

5678499

25

26

5677136

pub(super) fn parse_unquote(input: &mut &str) -> ModalResult<Expr> {

27

5677136

    let _ = ','.parse_next(input)?;

28

1500

    if input.starts_with('@') {

29

205

        let _ = '@'.parse_next(input)?;

30

205

        let expr = parse_expr.parse_next(input)?;

31

205

        return Ok(Expr::UnquoteSplicing(Box::new(expr)));

32

1295

33

1295

    let expr = parse_expr.parse_next(input)?;

34

1295

    Ok(Expr::Unquote(Box::new(expr)))

35

5677136

36

37

5675636

pub(super) fn parse_list(input: &mut &str) -> ModalResult<Expr> {

38

5675636

    let _ = '('.parse_next(input)?;

39

2193532

    skip_ws_and_comments_no_annotations(input)?;

40

41

2193532

    let mut items = Vec::new();

42

2193532

    let mut dotted_cdr: Option<Expr> = None;

43

44

    loop {

45

7594014

        if input.starts_with(')') {

46

2192302

            break;

47

5401712

48

5401712

        if input.is_empty() {

49

816

            return Err(ErrMode::Cut(

50

816

                ContextError::new()

51

816

                    .add_context(input, &input.checkpoint(), StrContext::Label("list"))

52

816

                    .add_context(

53

816

                        input,

54

816

                        &input.checkpoint(),

55

816

                        StrContext::Expected(StrContextValue::Description("closing paren")),

56

816

),

57

816

));

58

5400896

59

5400896

        if input.starts_with('.') && input.chars().nth(1).is_some_and(char::is_whitespace) {

60

6

            let _ = '.'.parse_next(input)?;

61

6

            skip_ws_and_comments_no_annotations(input)?;

62

6

            dotted_cdr = Some(

63

6

                cut_err(parse_expr)

64

6

                    .context(StrContext::Label("cdr expression"))

65

6

                    .parse_next(input)?,

66

);

67

6

            skip_ws_and_comments_no_annotations(input)?;

68

6

            cut_err(')')

69

6

                .context(StrContext::Label("closing paren"))

70

6

                .context(StrContext::Expected(StrContextValue::Description(

71

6

                    "only one expression after dot in dotted pair",

72

6

)))

73

6

                .parse_next(input)?;

74

5

            break;

75

5400890

76

5400890

        let expr = parse_expr(input)?;

77

5400482

        items.push(expr);

78

5400482

        skip_ws_and_comments_no_annotations(input)?;

79

80

81

2192307

    if dotted_cdr.is_none() {

82

2192302

        cut_err(')')

83

2192302

            .context(StrContext::Label("list"))

84

2192302

            .context(StrContext::Expected(StrContextValue::Description(

85

2192302

                "closing paren",

86

2192302

)))

87

2192302

            .parse_next(input)?;

88

5

89

90

2192307

    if let Some(cdr) = dotted_cdr {

91

5

        let mut result = cdr;

92

6

        for item in items.into_iter().rev() {

93

6

            result = Expr::cons(item, result);

94

6

95

5

        Ok(result)

96

    } else {

97

2192302

        Ok(Expr::List(items))

98

99

5675636