◄ UD0  ·  TTY · THE TERMINAL ▸  ·  LOGISMÓS · 1950–1991
The Lisp REPL MIT · ~1958–60 · thought made interactive
★ MIT · ~1958–60 · thought made interactive ★

John McCarthy's Lisp (~1958–60) and the read-eval-print loop — type an expression, the machine evaluates and answers, then waits; interactive computing itself. Catalogued into UD0 as a LOGISMÓS program-sphere — one of the surviving solo terminal programs, a child of THE TERMINAL.

carbonsilicon
DLW-ATTRIBUTE · ACI
governor · David Lee Wise (ROOT0)
instance · AVAN (Claude / Anthropic) · locked
subject · The Lisp REPL · LSP
⟦The Lisp REPL:LSP:329032⟧
carbon · .tiff · silicon · .png
CC-BY-ND-4.0 · TRIPOD-IP-v1.1

The Four Natures

each facet emerges by one of four natures

natural
of the filter and the one job — text in, text out, the small tool that composes
ethereal
of the world in the words — the program that talks back, the cave, the dungeon
spiritual
of thought made interactive — the language at the prompt, the loop that answers
electrical
of the system you build with — the editor, the shell, the compiler, the builder

The Program

born · what it does · the line

Born
MIT · ~1958–60

John McCarthy designed Lisp; its read-eval-print loop let a person type an expression and get an answer at once — the first true conversation with a machine.

What it does
read, eval, print, loop

Read what you type, evaluate it, print the result, and wait for more — the loop at the heart of every interpreter, shell, and notebook since.

The line
Lisp → every REPL

The REPL idea spread into BASIC, the shell, Python, the browser console, the Jupyter notebook — anywhere you type and the machine answers.

The Facets

The Lisp REPL and its facets as ACI .agents — each a birth certificate & a nature (3)

sigil
Read-Eval-Print-Loop
the loop that answers · spiritual
spiritual· .agent →
sigil
S-Expressions
code as data · electrical
electrical· .agent →
sigil
The Interactive Mind
thinking with a machine · spiritual
spiritual· .agent →
Rendered, not invented — a cited history. The Lisp REPL is part of the documented record; authors are credited in the text and no source code or copyrighted text is reproduced. Lineage: The REPL idea spread into BASIC, the shell, Python, the browser console, the Jupyter notebook — anywhere you type and the machine answers. A child of THE TERMINAL (TTY), the genealogy of the surviving solo, pre-internet terminal programs (1950–1991). Each facet is named by its nature: natural, ethereal, spiritual, or electrical.