input function

Readme.org

@@ -478,10 +478,6 @@ Note: this section only tracks the state of incomplete TODO items. Having everyt
 
 ** TODO Pre-alpha tasks
 - Shell prompt is fully configurable (History, L, R, and Delim)
-- Input function
-- Lex function
-- Read function (Input + Lex)
-- get type function
 - Shell module
   - Only loadable via POSIX config var
   - Overload Load function to hook into this lib
@@ -499,6 +495,9 @@ Note: this section only tracks the state of incomplete TODO items. Having everyt
 - Rename to Flesh
 - master branch -> main branch
 - Create a dedicated community channel on matrix.sunnypup.io
+- get type function
+- Lex function
+- Read function (Input + Lex)
 
 ** TODO post-alpha tasks
 - Post to relevant channels

src/stl.rs

@@ -595,6 +595,18 @@ pub fn static_stdlib(syms: &mut SymTable) -> Result<(), String> {
         }
     );
 
+    syms.insert(
+        "input".to_string(),
+        Symbol {
+            name: String::from("input"),
+            args: Args::Strict(vec![Type::String]),
+            conditional_branches: false,
+            docs: strings::INPUT_DOCSTRING.to_string(),
+            value: ValueType::Internal(Rc::new(strings::input_callback)),
+            ..Default::default()
+        }
+    );
+
     Ok(())
 }
 

src/stl/strings.rs

@@ -17,6 +17,8 @@
 
 use crate::segment::{Ctr, Seg};
 use crate::sym::SymTable;
+use std::io::Write;
+use std::io;
 
 pub const ECHO_DOCSTRING: &str =
     "traverses any number of arguments. Prints their evaluated values on a new line for each.";
@@ -150,3 +152,19 @@ pub fn split_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
 
     Ok(Ctr::Seg(ret))
 }
+
+pub const INPUT_DOCSTRING: &str = "Takes one argument (string) and prints it.
+Then prompts for user input.
+User input is returned as a string";
+
+pub fn input_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    if let Ctr::String(ref s) = *ast.car {
+        print!("{}", s);
+        let _= io::stdout().flush();
+        let mut input = String::new();
+        io::stdin().read_line(&mut input).expect("couldnt read user input");
+        Ok(Ctr::String(input.trim().to_string()))
+    } else {
+        Err("impossible: arg not string".to_string())
+    }
+}

src/sym.rs

@@ -101,10 +101,11 @@ impl SymTable {
          *   * sym is not in self
          *   * sym has a newer generation than the entry in self
          */
+        let tmp = self.1;
         for i in other.iter() {
             self.0.entry(i.0.to_string())
                 .and_modify(|inner: &mut Symbol| {
-                    if inner.__generation < i.1.__generation {
+                    if tmp < i.1.__generation {
                         inner.__generation = i.1.__generation;
                         inner.value = i.1.value.clone();
                         inner.args = i.1.args.clone();