evals-in-R-code.Rmd

---
title: "R Notebook"
output: html_notebook
---

```{r}
library(readr)
library(devtools)
library(dplyr)
library(stringr)
library(purrr)
library(Rcpp)
```


```{r}
cppFunction(
'
Rcpp::StringVector find_balanced_expression(std::string &s, int start) {
  int br = 0;
  bool done = false;
  int i = start - 1;

  if (i < 0 || i > s.length()) throw std::range_error("Invalid start location: " + start);

  for (; !done && i < s.length(); i++) {
    switch(s[i]) {
      case \'(\':
        br++;
        break;
      case \')\':
        br--;
        done = br == 0;
        break;
    }
  }

  
  Rcpp::StringVector ret = Rcpp::StringVector(NA_STRING);
  if (done) {
    ret(0) = s.substr(start, i - start - 1);
  }
  
  return ret;
}
')

find_evals_in_file <- function(path) {
  txt <- read_file(path)
  locs <- str_locate_all(txt, "eval\\(")
  args <- map_chr(locs[[1]][, 2], ~find_balanced_expression(txt, .))
  
  data_frame(file=path, start=locs[[1]][, 1], args=args)
}

find_evals <- function(path) {
  package <- as.package(path)
  r_dir <- file.path(path, "R")
  r_files <- list.files(r_dir, pattern="\\.[Rr]$", full.names=T, recursive=T)
  
  df <- map_dfr(r_files, ~ find_evals_in_file(.))
  bind_cols(data_frame(package=rep(package$package, nrow(df))), df)
}

```

```{r}
test_eval_str <- "asda \n eval(expr=parse(paste0(somefun('A'),\n 'B'))) sdf eval(quote(eval(quote(1+1))))"

find_balanced_expression(test_eval_str, str_locate_all(test_eval_str, "eval\\(")[[1]][1, 2])

find_evals_in_file("R/CRAN-extracted/devtools/R/source.r")

find_evals("R/CRAN-extracted/devtools")
```