In machow/straw: Code to AST Mappings, and Vice-versa

knitr::opts_chunk$set(echo = TRUE)

library(straw)
options(keep.source = TRUE)

expr <- parse(text = "
function(a = 1) {
  2
  3 + 3
}")

g <- create_parse_graph(expr)
g_ast <- create_parse_graph(expr, type = 'ast')

cytoscape_dagre(tbl_to_cyto(g))
g

ast <- enhance_ast(expr)
ast

find_code <- function (enhanced_ast, line1, col1, line2, col2) {
  code <- enhanced_ast[-1,]
  indx <- (
    code$line1 <= line1 & code$line2 >= line2 &
    code$col1 <= col1 & code$col2 >= col2
    )

  rects <- code[indx,]

  if (nrow(rects) == 1)
    return(rects)

  # find smallest bounding rectangle
  min_indx <- with(rects, which.min(line1 * line2 * col1 * col2))
  rects[min_indx,]
}

# find the smallest bounded rectangle
# line: 4, 4    column: 3, 3
find_code(ast, 4, 3, 4, 3)[,-c(2,3)]
find_code(ast, 4, 3, 4, 5)[,-c(2,3)]

expr2 <- parse(text = "
{
  3 + 3
}
")

ast <- enhance_ast(expr2)
find_code(ast, 3, 3, 3, 4)
ast

machow/straw documentation built on Sept. 9, 2020, 12:40 a.m.