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if(!exists("..readline..")) source("readline.r")
if(!exists("..types..")) source("types.r")
if(!exists("..reader..")) source("reader.r")
if(!exists("..printer..")) source("printer.r")
if(!exists("..env..")) source("env.r")
READ <- function(str) {
return(read_str(str))
}
eval_ast <- function(ast, env) {
if (.symbol_q(ast)) {
Env.get(env, ast)
} else if (.list_q(ast)) {
new.listl(lapply(ast, function(a) EVAL(a, env)))
} else if (.vector_q(ast)) {
new.vectorl(lapply(ast, function(a) EVAL(a, env)))
} else if (.hash_map_q(ast)) {
lst <- list()
for(k in ls(ast)) {
lst[[length(lst)+1]] = k
lst[[length(lst)+1]] = EVAL(ast[[k]], env)
}
new.hash_mapl(lst)
} else {
ast
}
}
EVAL <- function(ast, env) {
#cat("EVAL: ", .pr_str(ast,TRUE), "\n", sep="")
if (!.list_q(ast)) {
return(eval_ast(ast, env))
}
# apply list
switch(paste("l",length(ast),sep=""),
l0={ return(ast) },
l1={ a0 <- ast[[1]]; a1 <- NULL; a2 <- NULL },
l2={ a0 <- ast[[1]]; a1 <- ast[[2]]; a2 <- NULL },
{ a0 <- ast[[1]]; a1 <- ast[[2]]; a2 <- ast[[3]] })
a0sym <- as.character(a0)
if (a0sym == "def!") {
res <- EVAL(ast[[3]], env)
return(Env.set(env, a1, res))
} else if (a0sym == "let*") {
let_env <- new.Env(env)
for(i in seq(1,length(a1),2)) {
Env.set(let_env, a1[[i]], EVAL(a1[[i+1]], let_env))
}
return(EVAL(a2, let_env))
} else {
el <- eval_ast(ast, env)
f <- el[[1]]
return(do.call(f,slice(el,2)))
}
}
PRINT <- function(exp) {
return(.pr_str(exp, TRUE))
}
repl_env <- new.Env()
Env.set(repl_env, "+", function(a,b) a+b)
Env.set(repl_env, "-", function(a,b) a-b)
Env.set(repl_env, "*", function(a,b) a*b)
Env.set(repl_env, "/", function(a,b) a/b)
rep <- function(str) return(PRINT(EVAL(READ(str), repl_env)))
repeat {
line <- readline("user> ")
if (is.null(line)) { cat("\n"); break }
tryCatch({
cat(rep(line),"\n", sep="")
}, error=function(err) {
cat("Error: ", get_error(err),"\n", sep="")
})
# R debug/fatal with tracebacks:
#cat(rep(line),"\n", sep="")
}
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