1 files changed, 37 insertions, 0 deletions
diff --git a/src/field.nim b/src/field.nim
new file mode 100644
index 0000000..a9d26fc
--- /dev/null
+++ b/src/field.nim
@@ -0,0 +1,37 @@
+type
+  Line = ref object
+    x, l: int
+    columns: seq[int]
+
+  Field* = ref object
+    x, y: int
+    lx, ly: int
+    lines: seq[Line]
+
+proc get*(f: Field, x, y: int): int =
+  if y >= f.y and y < f.y + f.ly:
+    let l = f.lines[y-f.y]
+    if x >= l.x and x < l.x + l.l:
+      return l.columns[x-l.x]
+  return int(' ')
+
+proc isIn*(f: Field, x, y: int): bool =
+  return x >= f.x and y >= f.y and x < f.x+f.lx and y < f.y+f.ly
+
+when defined(unitTesting):
+  let minimal = Field(
+    x: 0,
+    y: 0,
+    lx: 1,
+    ly: 1,
+    lines: @[
+      Line(x: 0, l: 1, columns: @[int('@')])
+    ]
+  )
+  suite "Field":
+    test "Field.get":
+      check minimal.get(0,0) == int('@')
+      check minimal.get(1,0) == int(' ')
+    test "Field.isIn":
+      check minimal.isIn(0, 0) == true
+      check minimal.isIn(1, 0) == false