nu_cmd_lang/core_commands/
export_use.rs

1use nu_engine::{
2    command_prelude::*, find_in_dirs_env, get_dirs_var_from_call, get_eval_block, redirect_env,
3};
4use nu_protocol::{
5    ast::{Expr, Expression},
6    engine::CommandType,
7    shell_error::generic::GenericError,
8};
9
10#[derive(Clone)]
11pub struct ExportUse;
12
13impl Command for ExportUse {
14    fn name(&self) -> &str {
15        "export use"
16    }
17
18    fn description(&self) -> &str {
19        "Use definitions from a module and export them from this module."
20    }
21
22    fn signature(&self) -> nu_protocol::Signature {
23        Signature::build("export use")
24            .input_output_types(vec![(Type::Nothing, Type::Nothing)])
25            .param(Parameter::Required(
26                PositionalArg::new("module", SyntaxShape::String)
27                    .desc("Module or module file.")
28                    .completion(Completion::Builtin(BuiltinCompletion::NuFile {
29                        std_virtual_path: true,
30                    })),
31            ))
32            .param(Parameter::Rest(
33                PositionalArg::new("members", SyntaxShape::Any)
34                    .desc("Which members of the module to import.")
35                    .completion(Completion::Builtin(BuiltinCompletion::ModuleExports)),
36            ))
37            .category(Category::Core)
38    }
39
40    fn extra_description(&self) -> &str {
41        "This command is a parser keyword. For details, check:
42  https://www.nushell.sh/book/thinking_in_nu.html"
43    }
44
45    fn command_type(&self) -> CommandType {
46        CommandType::Keyword
47    }
48
49    fn run(
50        &self,
51        engine_state: &EngineState,
52        caller_stack: &mut Stack,
53        call: &Call,
54        input: PipelineData,
55    ) -> Result<PipelineData, ShellError> {
56        if call.get_parser_info(caller_stack, "noop").is_some() {
57            return Ok(PipelineData::empty());
58        }
59        let Some(Expression {
60            expr: Expr::ImportPattern(import_pattern),
61            ..
62        }) = call.get_parser_info(caller_stack, "import_pattern")
63        else {
64            return Err(ShellError::Generic(GenericError::new(
65                "Unexpected import",
66                "import pattern not supported",
67                call.head,
68            )));
69        };
70
71        // Necessary so that we can modify the stack.
72        let import_pattern = import_pattern.clone();
73
74        if let Some(module_id) = import_pattern.head.id {
75            // Add constants
76            for var_id in &import_pattern.constants {
77                let var = engine_state.get_var(*var_id);
78
79                if let Some(constval) = &var.const_val {
80                    caller_stack.add_var(*var_id, constval.clone());
81                } else {
82                    return Err(ShellError::NushellFailedSpanned {
83                        msg: "Missing Constant".to_string(),
84                        label: "constant not added by the parser".to_string(),
85                        span: var.declaration_span,
86                    });
87                }
88            }
89
90            // Evaluate the export-env block if there is one
91            let module = engine_state.get_module(module_id);
92
93            if let Some(block_id) = module.env_block {
94                let block = engine_state.get_block(block_id);
95
96                // See if the module is a file
97                let module_arg_str = String::from_utf8_lossy(
98                    engine_state.get_span_contents(import_pattern.head.span),
99                );
100
101                let maybe_file_path_or_dir = find_in_dirs_env(
102                    &module_arg_str,
103                    engine_state,
104                    caller_stack,
105                    get_dirs_var_from_call(caller_stack, call),
106                )?;
107                // module_arg_str maybe a directory, in this case
108                // find_in_dirs_env returns a directory.
109                let maybe_parent = maybe_file_path_or_dir.as_ref().and_then(|path| {
110                    if path.is_dir() {
111                        Some(path.to_path_buf())
112                    } else {
113                        path.parent().map(|p| p.to_path_buf())
114                    }
115                });
116
117                let mut callee_stack = caller_stack
118                    .gather_captures(engine_state, &block.captures)
119                    .reset_pipes();
120
121                // If so, set the currently evaluated directory (file-relative PWD)
122                if let Some(parent) = maybe_parent {
123                    let file_pwd = Value::string(parent.to_string_lossy(), call.head);
124                    callee_stack.add_env_var("FILE_PWD".to_string(), file_pwd);
125                }
126
127                if let Some(path) = maybe_file_path_or_dir {
128                    let module_file_path = if path.is_dir() {
129                        // the existence of `mod.nu` is verified in parsing time
130                        // so it's safe to use it here.
131                        Value::string(path.join("mod.nu").to_string_lossy(), call.head)
132                    } else {
133                        Value::string(path.to_string_lossy(), call.head)
134                    };
135                    callee_stack.add_env_var("CURRENT_FILE".to_string(), module_file_path);
136                }
137
138                let eval_block = get_eval_block(engine_state);
139
140                // Run the block (discard the result)
141                let _ = eval_block(engine_state, &mut callee_stack, block, input)?;
142
143                // Merge the block's environment to the current stack
144                redirect_env(engine_state, caller_stack, &callee_stack);
145            }
146        } else {
147            return Err(ShellError::Generic(GenericError::new(
148                format!(
149                    "Could not import from '{}'",
150                    String::from_utf8_lossy(&import_pattern.head.name)
151                ),
152                "module does not exist",
153                import_pattern.head.span,
154            )));
155        }
156
157        Ok(PipelineData::empty())
158    }
159
160    fn examples(&self) -> Vec<Example<'_>> {
161        vec![Example {
162            description: "Re-export a command from another module.",
163            example: r#"module spam { export def foo [] { "foo" } }
164    module eggs { export use spam foo }
165    use eggs foo
166    foo
167            "#,
168            result: Some(Value::test_string("foo")),
169        }]
170    }
171
172    fn search_terms(&self) -> Vec<&str> {
173        vec!["reexport", "import", "module"]
174    }
175}
nu_cmd_lang/core_commands/export_use.rs

nu_cmd_lang/core_commands/
export_use.rs
