tree generator, Python

Language: Layout:

#python 2.7.12
'''Created by Elijah Bascuti'''
WITH
params AS(
    SELECT 
        --- tree params
        30 as _p_halfwidth, -- max half width of the tree 
        4 as _p_height,  -- heigt of single tree block
        5 as _p_num_blocks,  -- number of tree blocks
        1.1 as _p_scale_inter,  -- inter scale of block widening
        1.15 as _p_scale_outer,   --- outer scale of blocks

---- the look of tree
        '.'::text as _p_tree_char,
        'X'::text as _p_star_char,
        'x'::text as _p_chain_char,
        'O'::text as _p_decor1_char,
        '8'::text as _p_decor2_char,

--- density and location of decors :

3 as _p_chain_start,
        0 as _p_decor1_start,
        0 as _p_decor2_start,
        
        2 as _p_chain_helicity,
        1 as _p_decor1_helicity,
        1 as _p_decor2_helicity,
        
        8 as _p_chain_step,
        5 as _p_decor1_step,
        7 as _p_decor2_step,
        
        0.99 as _p_chain_prob, -- chain sometimes ends...
        0.1 as _p_decor1_prob,
        0.1 as _p_decor2_prob   
    ),
christmas_tree as (
        ---- build a table of float numbers b in blocks_
    WITH  RECURSIVE tree(b, pos,l, lv) AS ( 
        (WITH RECURSIVE t(b,pos, l) AS (
            SELECT 
                1 -(abs(generate_series(-_p_halfwidth, _p_halfwidth, 1)))::float8 /(_p_halfwidth) b, -- to draw tree
                generate_series (0, 2*_p_halfwidth, 1) as  pos, -- to find positions of decorations
                0 as l from params
            UNION ALL
            SELECT (b *_p_scale_inter), pos, l + 1 FROM t,params WHERE l < _p_height-1
        )
        select b, pos, l, 1 AS lv from t order by l asc
    )
    UNION ALL
    SELECT b * _p_scale_outer, pos, l + (lv * (2*_p_halfwidth+1)) AS l, lv + 1
    FROM tree,params
    WHERE lv < _p_num_blocks
    )

select l,array_to_string(array_agg(
        (CASE 
            WHEN b>=1 THEN 
            CASE
                WHEN l=0 THEN _p_star_char
                ELSE
                    CASE
                        WHEN mod(pos+_p_chain_helicity*l + _p_chain_start,_p_chain_step)=0 and random()<_p_chain_prob  THEN _p_chain_char
                        WHEN mod(pos+_p_decor1_helicity*l + _p_decor1_start,_p_decor1_step)=0 and random()<_p_decor1_prob  THEN _p_decor1_char
                        WHEN mod(pos+_p_decor2_helicity*l + _p_decor2_start,_p_decor2_step)=0 and random()<_p_decor2_prob THEN _p_decor2_char               
                    ELSE _p_tree_char
                    END 
            END
        ELSE ' ' 
        END)::text), ''
    ) AS "Merry Christmas"
    from tree,params
    group by l
    order by l asc
)
select "Merry Christmas" from christmas_tree
order by l

[ + ] Show input
Absolute running time: 0.1 sec, cpu time: 0.04 sec, memory peak: 4 Mb, absolute service time: 0,11 sec