Published at Mar 13 2019
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Instructions

Test suite

Solution

Given a diagram, determine which plants each child in the kindergarten class is responsible for.

The kindergarten class is learning about growing plants. The teacher thought it would be a good idea to give them actual seeds, plant them in actual dirt, and grow actual plants.

They've chosen to grow grass, clover, radishes, and violets.

To this end, the children have put little cups along the window sills, and planted one type of plant in each cup, choosing randomly from the available types of seeds.

```
[window][window][window]
........................ # each dot represents a cup
........................
```

There are 12 children in the class:

- Alice, Bob, Charlie, David,
- Eve, Fred, Ginny, Harriet,
- Ileana, Joseph, Kincaid, and Larry.

Each child gets 4 cups, two on each row. Their teacher assigns cups to the children alphabetically by their names.

The following diagram represents Alice's plants:

```
[window][window][window]
VR......................
RG......................
```

In the first row, nearest the windows, she has a violet and a radish. In the second row she has a radish and some grass.

Your program will be given the plants from left-to-right starting with the row nearest the windows. From this, it should be able to determine which plants belong to each student.

For example, if it's told that the garden looks like so:

```
[window][window][window]
VRCGVVRVCGGCCGVRGCVCGCGV
VRCCCGCRRGVCGCRVVCVGCGCV
```

Then if asked for Alice's plants, it should provide:

- Violets, radishes, violets, radishes

While asking for Bob's plants would yield:

- Clover, grass, clover, clover

To run the tests, run the command `busted`

from within the exercise directory.

For more detailed information about the Lua track, including how to get help if you're having trouble, please visit the exercism.io Lua language page.

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It's possible to submit an incomplete solution so you can see how others have completed the exercise.

```
local Garden = require('kindergarten-garden')
describe('kindergarten-garden', function()
it('should be able to parse a garden with only one student', function()
local garden = Garden('RC\nGG')
assert.same({ 'radishes', 'clover', 'grass', 'grass' }, garden.alice)
end)
it('should be able to parse a graden with more than one student', function()
local garden = Garden('VVCG\nVVRC')
assert.same({ 'violets', 'violets', 'violets', 'violets' }, garden.alice)
assert.same({ 'clover', 'grass', 'radishes', 'clover' }, garden.bob)
end)
it('should be able to parse a garden with plants for all students', function()
local garden = Garden('VRCGVVRVCGGCCGVRGCVCGCGV\nVRCCCGCRRGVCGCRVVCVGCGCV')
assert.same({ 'violets', 'radishes', 'violets', 'radishes' }, garden.alice)
assert.same({ 'clover', 'grass', 'clover', 'clover' }, garden.bob)
assert.same({ 'violets', 'violets', 'clover', 'grass' }, garden.charlie)
assert.same({ 'radishes', 'violets', 'clover', 'radishes' }, garden.david)
assert.same({ 'clover', 'grass', 'radishes', 'grass' }, garden.eve)
assert.same({ 'grass', 'clover', 'violets', 'clover' }, garden.fred)
assert.same({ 'clover', 'grass', 'grass', 'clover' }, garden.ginny)
assert.same({ 'violets', 'radishes', 'radishes', 'violets' }, garden.harriet)
assert.same({ 'grass', 'clover', 'violets', 'clover' }, garden.ileana)
assert.same({ 'violets', 'clover', 'violets', 'grass' }, garden.joseph)
assert.same({ 'grass', 'clover', 'clover', 'grass' }, garden.kincaid)
assert.same({ 'grass', 'violets', 'clover', 'violets' }, garden.larry)
end)
it('should return an empty result for students that are not present', function()
local garden = Garden('RC\nGG')
assert.same({}, garden.bob)
end)
it('should return an empty result for students that do not exist', function()
local garden = Garden('RC\nGG')
assert.same({}, garden.katrina)
end)
it('should ignore case for gardens', function()
local garden = Garden('Rc\ngG')
assert.same({ 'radishes', 'clover', 'grass', 'grass' }, garden.alice)
end)
it('should ignore case for students', function()
local garden = Garden('RC\nGG')
assert.same({ 'radishes', 'clover', 'grass', 'grass' }, garden.ALICE)
end)
end)
```

```
local PLANTS = {
C = 'clover', G = 'grass', R = 'radishes', V = 'violets',
}
local STUDENTS = {
'Alice', 'Bob', 'Charlie', 'David', 'Eve', 'Fred',
'Ginny', 'Harriet', 'Ileana', 'Joseph', 'Kincaid', 'Larry',
}
local parse
local plots
local Garden = function(input)
return setmetatable(parse(input:upper()), {
__index = function(table, key)
--[[ indexing the table within the __index
-- metamethod can lead to an infinite loop:
return table[key:lower()] or {}
--]]
local keyl = key:lower()
for k,v in pairs(table) do
if k == keyl then return v end
end
return {}
end,
})
end
parse = function(input)
-- input must contain a newline, and
-- the newline must be in the center
local idx = input:find("\n")
assert(idx and idx == 1 + #input//2, 'Malformed input')
local garden = {}
local i = 1
for plot in plots(input:sub(1,idx-1), input:sub(idx+1)) do
garden[STUDENTS[i]:lower()] = plot
i = i + 1
end
return garden
end
plots = function(row1, row2)
return coroutine.wrap(function()
for i = 1, #row1, 2 do
local patch = row1:sub(i,i+1) .. row2:sub(i,i+1)
local plants = {}
for p in patch:gmatch(".") do
plants[#plants+1] = PLANTS[p] or "Unknown"
end
coroutine.yield(plants)
end
end)
end
return Garden
```

A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.

Here are some questions to help you reflect on this solution and learn the most from it.

- What compromises have been made?
- Are there new concepts here that you could read more about to improve your understanding?

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