mamba 0.3.6

A transpiler which converts Mamba files to Python 3 files
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136

use std::convert::TryFrom;

use crate::check::constrain::constraint::builder::ConstrBuilder;
use crate::check::constrain::constraint::Constraint;
use crate::check::constrain::constraint::expected::Expected;
use crate::check::constrain::generate::{Constrained, generate};
use crate::check::constrain::generate::collection::constr_col_lookup;
use crate::check::constrain::generate::env::Environment;
use crate::check::context::Context;
use crate::check::name::true_name::TrueName;
use crate::check::result::TypeErr;
use crate::parse::ast::{AST, Node};

pub fn gen_flow(
    ast: &AST,
    env: &Environment,
    ctx: &Context,
    constr: &mut ConstrBuilder,
) -> Constrained {
    match &ast.node {
        Node::Handle { expr_or_stmt, cases } => {
            let (raises, errs): (Vec<Result<_, _>>, Vec<Result<_, _>>) = cases.iter().map(|c| match &c.node {
                Node::Case { cond, .. } => {
                    match &cond.node {
                        Node::ExpressionType { ty: Some(ty), .. } => TrueName::try_from(ty)
                            .map_err(|errs| errs.first().expect("At least one").clone()),
                        other => {
                            let msg = format!("Expected type identifier, was {other}");
                            Err(TypeErr::new(cond.pos, &msg))
                        }
                    }
                }
                other => Err(TypeErr::new(c.pos, &format!("Expected case, was {other}")))
            }).partition(Result::is_ok);

            if !errs.is_empty() { return Err(errs.into_iter().map(Result::unwrap_err).collect()); }
            let raises = raises.into_iter().map(Result::unwrap).collect();

            let raises_before = env.raises_caught.clone();
            let outer_env = generate(expr_or_stmt, &env.raises_caught(&raises), ctx, constr)?
                .raises_caught(&raises_before);

            constrain_cases(ast, &None, cases, &outer_env, ctx, constr)?;
            Ok(outer_env.clone())
        }

        Node::IfElse { cond, then, el: Some(el) } => {
            constr.add_constr(&Constraint::truthy("if condition", &Expected::from(cond)), env);
            generate(cond, env, ctx, constr)?;
            let if_expr_exp = Expected::from(ast);

            constr.branch_point();
            generate(then, env, ctx, constr)?;
            if env.is_expr {
                constr.add("then branch equal to if", &if_expr_exp, &Expected::from(then), env);
            }

            constr.branch("if else branch", el.pos);
            generate(el, env, ctx, constr)?;
            if env.is_expr {
                constr.add("else branch equal to if", &if_expr_exp, &Expected::from(el), env);
            }

            constr.reset_branches();
            Ok(env.clone())
        }
        Node::IfElse { cond, then, .. } => {
            constr.add_constr(&Constraint::truthy("if condition", &Expected::from(cond)), env);

            generate(cond, env, ctx, constr)?;
            generate(then, env, ctx, constr)?;
            Ok(env.clone())
        }

        Node::Case { .. } => Err(vec![TypeErr::new(ast.pos, "Case cannot be top level")]),
        Node::Match { cond, cases } => {
            let outer_env = generate(cond, env, ctx, constr)?;
            constrain_cases(ast, &Some(*cond.clone()), cases, &outer_env, ctx, constr)?;
            Ok(env.clone())
        }

        Node::For { expr, col, body } => {
            let col_env = generate(col, env, ctx, constr)?;
            let lookup_env = constr_col_lookup(expr, col, &col_env.is_def_mode(true), constr)?
                .is_def_mode(false);
            let lookup_env = generate(expr, &lookup_env, ctx, constr)?;

            generate(body, &lookup_env.in_loop(), ctx, constr)?;
            Ok(env.clone())
        }
        Node::While { cond, body } => {
            constr.add_constr(&Constraint::truthy("while condition", &Expected::from(cond)), env);

            generate(cond, env, ctx, constr)?;
            generate(body, &env.in_loop(), ctx, constr)?;
            Ok(env.clone())
        }

        Node::Break | Node::Continue if env.in_loop => Ok(env.clone()),
        Node::Break | Node::Continue => Err(vec![TypeErr::new(ast.pos, "Cannot be outside loop")]),

        _ => Err(vec![TypeErr::new(ast.pos, "Expected control flow")])
    }
}

fn constrain_cases(ast: &AST, expr: &Option<AST>, cases: &Vec<AST>, env: &Environment, ctx: &Context, constr: &mut ConstrBuilder) -> Constrained<()> {
    let is_define_mode = env.is_def_mode;
    constr.branch_point();

    for case in cases {
        match &case.node {
            Node::Case { cond, body } => {
                constr.branch("match arm", case.pos);
                let cond_env = generate(cond, &env.is_def_mode(true), ctx, constr)?;

                if let Node::ExpressionType { expr: ref cond, .. } = cond.node {
                    if let Some(expr) = &expr {
                        constr.add("arm body", &Expected::from(expr), &Expected::from(cond), env);
                    }
                }

                generate(body, &cond_env.is_def_mode(is_define_mode), ctx, constr)?;
                let exp_body = Expected::from(body);
                constr.add("arm body", &exp_body, &Expected::from(ast), env);

                if env.is_expr {
                    constr.add("arm body and outer", &Expected::from(ast), &exp_body, env);
                }
            }
            _ => return Err(vec![TypeErr::new(case.pos, "Expected case")])
        }
    }

    constr.reset_branches();
    Ok(())
}