schala/schala-repl/src/repl/command_tree.rs

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use super::{Repl, InterpreterDirectiveOutput};
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use crate::repl::directive_actions::DirectiveAction;
use colored::*;
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/// A CommandTree is either a `Terminal` or a `NonTerminal`. When command parsing reaches the first
/// Terminal, it will use the `DirectiveAction` found there to find an appropriate function to execute,
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/// and then execute it with any remaining arguments
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#[derive(Clone)]
pub enum CommandTree {
Terminal {
name: String,
children: Vec<CommandTree>,
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help_msg: Option<String>,
action: DirectiveAction,
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},
NonTerminal {
name: String,
children: Vec<CommandTree>,
help_msg: Option<String>,
action: DirectiveAction,
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},
Top(Vec<CommandTree>),
}
impl CommandTree {
pub fn nonterm_no_further_tab_completions(s: &str, help: Option<&str>) -> CommandTree {
CommandTree::NonTerminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), children: vec![], action: DirectiveAction::Null }
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}
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pub fn terminal(s: &str, help: Option<&str>, children: Vec<CommandTree>, action: DirectiveAction) -> CommandTree {
CommandTree::Terminal {name: s.to_string(), help_msg: help.map(|x| x.to_string()), children, action}
}
pub fn nonterm(s: &str, help: Option<&str>, children: Vec<CommandTree>) -> CommandTree {
CommandTree::NonTerminal {
name: s.to_string(),
help_msg: help.map(|x| x.to_string()),
children,
action: DirectiveAction::Null
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}
}
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pub fn get_cmd(&self) -> &str {
match self {
CommandTree::Terminal { name, .. } => name.as_str(),
CommandTree::NonTerminal {name, ..} => name.as_str(),
CommandTree::Top(_) => "",
}
}
pub fn get_help(&self) -> &str {
match self {
CommandTree::Terminal { help_msg, ..} => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
CommandTree::NonTerminal { help_msg, .. } => help_msg.as_ref().map(|s| s.as_str()).unwrap_or(""),
CommandTree::Top(_) => ""
}
}
pub fn get_children(&self) -> Vec<&str> {
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use CommandTree::*;
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match self {
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Terminal { children, .. } |
NonTerminal { children, .. } |
Top(children) => children.iter().map(|x| x.get_cmd()).collect()
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}
}
pub fn perform(&self, repl: &mut Repl, arguments: &Vec<&str>) -> InterpreterDirectiveOutput {
let mut dir_pointer: &CommandTree = self;
let mut idx = 0;
let res: Result<(DirectiveAction, usize), String> = loop {
match dir_pointer {
CommandTree::Top(subcommands) | CommandTree::NonTerminal { children: subcommands, .. } => {
let next_command = match arguments.get(idx) {
Some(cmd) => cmd,
None => break Err(format!("Command requires arguments"))
};
idx += 1;
match subcommands.iter().find(|sc| sc.get_cmd() == *next_command) {
Some(command_tree) => {
dir_pointer = command_tree;
},
None => break Err(format!("Command {} not found", next_command))
};
},
CommandTree::Terminal { action, .. } => {
break Ok((action.clone(), idx));
},
}
};
match res {
Ok((action, idx)) => action.perform(repl, &arguments[idx..]),
Err(err) => Some(err.red().to_string())
}
}
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}