| 1 | if(!exists("..readline..")) source("readline.r") |
| 2 | if(!exists("..types..")) source("types.r") |
| 3 | if(!exists("..reader..")) source("reader.r") |
| 4 | if(!exists("..printer..")) source("printer.r") |
| 5 | if(!exists("..env..")) source("env.r") |
| 6 | if(!exists("..core..")) source("core.r") |
| 7 | |
| 8 | # read |
| 9 | READ <- function(str) { |
| 10 | return(read_str(str)) |
| 11 | } |
| 12 | |
| 13 | eval_ast <- function(ast, env) { |
| 14 | if (.symbol_q(ast)) { |
| 15 | Env.get(env, ast) |
| 16 | } else if (.list_q(ast)) { |
| 17 | new.listl(lapply(ast, function(a) EVAL(a, env))) |
| 18 | } else if (.vector_q(ast)) { |
| 19 | new.vectorl(lapply(ast, function(a) EVAL(a, env))) |
| 20 | } else if (.hash_map_q(ast)) { |
| 21 | lst <- list() |
| 22 | for(k in ls(ast)) { |
| 23 | lst[[length(lst)+1]] = k |
| 24 | lst[[length(lst)+1]] = EVAL(ast[[k]], env) |
| 25 | } |
| 26 | new.hash_mapl(lst) |
| 27 | } else { |
| 28 | ast |
| 29 | } |
| 30 | } |
| 31 | |
| 32 | EVAL <- function(ast, env) { |
| 33 | repeat { |
| 34 | |
| 35 | #cat("EVAL: ", .pr_str(ast,TRUE), "\n", sep="") |
| 36 | if (!.list_q(ast)) { |
| 37 | return(eval_ast(ast, env)) |
| 38 | } |
| 39 | |
| 40 | # apply list |
| 41 | switch(paste("l",length(ast),sep=""), |
| 42 | l0={ return(ast) }, |
| 43 | l1={ a0 <- ast[[1]]; a1 <- NULL; a2 <- NULL }, |
| 44 | l2={ a0 <- ast[[1]]; a1 <- ast[[2]]; a2 <- NULL }, |
| 45 | { a0 <- ast[[1]]; a1 <- ast[[2]]; a2 <- ast[[3]] }) |
| 46 | if (length(a0) > 1) a0sym <- "__<*fn*>__" |
| 47 | else a0sym <- as.character(a0) |
| 48 | if (a0sym == "def!") { |
| 49 | res <- EVAL(a2, env) |
| 50 | return(Env.set(env, a1, res)) |
| 51 | } else if (a0sym == "let*") { |
| 52 | let_env <- new.Env(env) |
| 53 | for(i in seq(1,length(a1),2)) { |
| 54 | Env.set(let_env, a1[[i]], EVAL(a1[[i+1]], let_env)) |
| 55 | } |
| 56 | ast <- a2 |
| 57 | env <- let_env |
| 58 | } else if (a0sym == "do") { |
| 59 | eval_ast(slice(ast,2,length(ast)-1), env) |
| 60 | ast <- ast[[length(ast)]] |
| 61 | } else if (a0sym == "if") { |
| 62 | cond <- EVAL(a1, env) |
| 63 | if (.nil_q(cond) || identical(cond, FALSE)) { |
| 64 | if (length(ast) < 4) return(nil) |
| 65 | ast <- ast[[4]] |
| 66 | } else { |
| 67 | ast <- a2 |
| 68 | } |
| 69 | } else if (a0sym == "fn*") { |
| 70 | return(malfunc(EVAL, a2, env, a1)) |
| 71 | } else { |
| 72 | el <- eval_ast(ast, env) |
| 73 | f <- el[[1]] |
| 74 | if (class(f) == "MalFunc") { |
| 75 | ast <- f$ast |
| 76 | env <- f$gen_env(slice(el,2)) |
| 77 | } else { |
| 78 | return(do.call(f,slice(el,2))) |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | } |
| 83 | } |
| 84 | |
| 85 | # print |
| 86 | PRINT <- function(exp) { |
| 87 | return(.pr_str(exp, TRUE)) |
| 88 | } |
| 89 | |
| 90 | # repl loop |
| 91 | repl_env <- new.Env() |
| 92 | rep <- function(str) return(PRINT(EVAL(READ(str), repl_env))) |
| 93 | |
| 94 | # core.r: defined using R |
| 95 | for(k in names(core_ns)) { Env.set(repl_env, k, core_ns[[k]]) } |
| 96 | Env.set(repl_env, "eval", function(ast) EVAL(ast, repl_env)) |
| 97 | Env.set(repl_env, "*ARGV*", new.list()) |
| 98 | |
| 99 | # core.mal: defined using the language itself |
| 100 | . <- rep("(def! not (fn* (a) (if a false true)))") |
| 101 | . <- rep("(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))") |
| 102 | |
| 103 | args <- commandArgs(trailingOnly = TRUE) |
| 104 | if (length(args) > 0) { |
| 105 | Env.set(repl_env, "*ARGV*", new.listl(slice(as.list(args),2))) |
| 106 | . <- rep(concat("(load-file \"", args[[1]], "\")")) |
| 107 | quit(save="no", status=0) |
| 108 | } |
| 109 | |
| 110 | repeat { |
| 111 | line <- readline("user> ") |
| 112 | if (is.null(line)) { cat("\n"); break } |
| 113 | tryCatch({ |
| 114 | cat(rep(line),"\n", sep="") |
| 115 | }, error=function(err) { |
| 116 | cat("Error: ", get_error(err),"\n", sep="") |
| 117 | }) |
| 118 | # R debug/fatal with tracebacks: |
| 119 | #cat(rep(line),"\n", sep="") |
| 120 | } |