variables.md

Variables in TechScript

Status: Implemented & Canonical

Variables in TechScript are dynamically typed, strictly scoped, and follow the canonical declaration and reassignment grammar.

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🏷️ Declaration (is)

TechScript uses is for declaring and binding a new variable:

name is "Alice"
age is 30
is_active is true

If you attempt to access an identifier before defining it, the compiler triggers an undefined variable diagnostic (TSE0300):

say undefined_var # Compile error!

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🔒 Constants (constant ... is)

Immutable values are declared using constant:

constant max_attempts is 5
constant app_name is "TechScript"

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🔄 Reassignment (becomes)

To change the value of an existing variable, use becomes:

count is 0
say "Initial: {count}"     # Initial: 0

count becomes count + 1
say "Updated: {count}"     # Updated: 1

x is 42
say "Number: {x}"

x becomes "Now a string"
say "Text: {x}"

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🧬 Scoping Rules

TechScript uses lexical scoping with indentation blocks. Variables defined inside a function, loop, or conditional are not accessible outside that block:

to process():
    local_val is 100
    say "Inside: {local_val}"

process()
# say local_val  # Compile error: local_val is out of scope

Inner blocks can shadow variables from outer scopes:

x is 5
if true:
    x is 10 # Shadows outer x within block
    say "Block x: {x}" # 10

say "Outer x: {x}"     # 5