Triggering the Code-as-Data Mindset in Pre-Tertiary Programmers: A Pedagogical Synthesis

The code-as-data mindset shift is the cognitive reframing from "code is a static instruction sequence written by humans for the machine" to "code is itself a manipulable data object — a string the interpreter consumes, a function-value bound to a name, an argument passed across boundaries, an abstract syntax tree the runtime walks". The shift gates the entire abstraction-growth pathway above procedural fluency: closures, decorators, higher-order combinators, meta-programming, interpreter writing, and the contemporary prompt-as-program reframing under generative tooling. Pre-tertiary curricula — including Vietnamese THCS / THPT informatics — almost universally defer the shift to tertiary education, leaving the largest abstraction-growth gate closed at the moment learners are otherwise ready for it. This paper synthesises four decades of pedagogical literature — from Abelson-Sussman's Structure and Interpretation of Computer Programs meta-circular evaluator through the Bootstrap curriculum line, Booth's phenomenographic studies, Caspersen's model-driven function pedagogy, Sorva's notional-machine analysis of first-class functions, Kohn's Python binding model, Ramalho's Fluent Python idiom corpus, the Maes / Bracha-Ungar reflective-programming line, Hermans's Hedy gradual-syntax work, and 2024 LLM-era promptpedagogy literature — to produce two contributions. First, a trigger catalogue of six named, ordered Python-idiomatic triggers (T1 string-as-program with eval / exec, T2 function-as-variable assignment, T3 function-as-argument via map / sorted(key=...), T4 function-as-return-value / closure, T5 decorator, T6 AST / dis introspection), each specified with definition, cognitive readiness threshold, prerequisite chain, Python-idiomatic minimal example, documented novice misconception, success indicator, and Python Pathway / From-Scratch-to-Python deployment slot. Second, a trigger-design argument that the concrete-then-symbolic ordering of these six triggers — modelled on Bruner enactive-iconicsymbolic and Goldstone-Son concreteness fading — is the loadbearing curriculum lever, and that the curriculum's choice of whether to deploy this ordering at the pre-tertiary level is a strategic decision with greater downstream impact than the choice of language family or editor environment. Per the elix-researches no-cohort scope, the catalogue is described and theoretically validated against the published-error corpus; deployment is identified as a downstream textbook responsibility (PP Vol 3–4, FS2P Vol 3–4). The strongest novel claim is the trigger-ordering claim: the six triggers are not interchangeable, the order is non-arbitrary, and skipping any trigger blocks the next one's success.