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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

use crate::{
    error::CrateResult,
    into_value::IntoValue,
    utils::{parse_nu_script, NewEmpty},
};
use std::env;

use nu_protocol::{
    ast::Block,
    engine::{Command, EngineState, Stack, StateWorkingSet},
    PipelineData, Span,
};

use super::{CommandGroupConfig, Context};

/// Builder to create a new nu engine state
pub struct ContextBuilder {
    engine_state: EngineState,
    stack: Stack,
    blocks: Vec<Block>,
}

impl Default for ContextBuilder {
    fn default() -> Self {
        Self {
            engine_state: EngineState::new(),
            stack: Stack::new(),
            blocks: Vec::new(),
        }
    }
}

impl ContextBuilder {
    /// Enables certain command groups specified in the Config on the state
    pub fn with_command_groups(mut self, group_config: CommandGroupConfig) -> CrateResult<Self> {
        macro_rules! toggle_command_groups {
            ($($group:ident),*) => {
                paste::item!(
                $(
                    if group_config.$group {
                        super::bindings::[<bind_ $group _commands>](&mut self.engine_state)?;
                    }
                )*
                )
            }
        }

        toggle_command_groups!(
            core,
            debug,
            filter,
            chart,
            misc,
            path,
            system,
            string,
            byte,
            file_system,
            platform,
            date,
            shell,
            format,
            viewer,
            conversion,
            environment,
            math,
            network,
            random,
            generator,
            hash,
            experimental
        );
        Ok(self)
    }

    /// Adds a custom command to the engine that can be used inside nu expressions
    /// This method can also be used to pass nu builtin commands to enable single commands
    /// Instead of whole command groups
    pub fn add_command<C: Command + 'static>(mut self, command: C) -> CrateResult<Self> {
        let mut working_set = StateWorkingSet::new(&self.engine_state);
        working_set.add_decl(Box::new(command));
        let delta = working_set.render();
        self.engine_state.merge_delta(delta)?;

        Ok(self)
    }

    /// Adds a variable to the state
    pub fn add_var<S: ToString, V: IntoValue>(mut self, name: S, value: V) -> CrateResult<Self> {
        let mut working_set = StateWorkingSet::new(&self.engine_state);

        let var_id = working_set.add_variable(
            name.to_string().into_bytes(),
            Span::empty(),
            nu_protocol::Type::Any,
            false,
        );
        self.stack.add_var(var_id, value.into_value());
        let delta = working_set.render();
        self.engine_state.merge_delta(delta)?;

        Ok(self)
    }

    /// Adds an environment variable to the state
    pub fn add_env_var<S: ToString, V: IntoValue>(mut self, name: S, value: V) -> Self {
        self.engine_state
            .add_env_var(name.to_string(), value.into_value());

        self
    }

    /// Adds the environment variables of the parent process to the
    /// states env variables
    pub fn add_parent_env_vars(self) -> Self {
        let mut builder = self;

        for (name, val) in env::vars() {
            builder = builder.add_env_var(name, val);
        }

        builder
    }

    /// Adds a block to the builder
    /// This block is evaluated when building to put
    /// the blocks contents in scope.
    /// Note: Code not contained in declarations is being executed when building
    ///       the context
    pub fn add_block(mut self, block: Block) -> Self {
        self.blocks.push(block);

        self
    }

    /// Adds a script to the context.
    /// This script is being parsed so this operation can fail
    pub fn add_script(mut self, contents: String) -> CrateResult<Self> {
        let block = parse_nu_script(&mut self.engine_state, contents)?;
        self.blocks.push(block);

        Ok(self)
    }

    /// builds the context
    pub fn build(self) -> CrateResult<Context> {
        let mut ctx = Context {
            engine_state: self.engine_state,
            stack: self.stack,
        };
        for block in self.blocks {
            ctx.eval_block(&block, PipelineData::empty())?;
        }

        Ok(ctx)
    }
}